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_„ Cornell University Library 

QB 36.B81D77 

Tycho Brahe; a picture of scientific life 

3 1924 005 641 380 

Cornell University 

The original of tliis book is in 
tine Cornell University Library. 

There are no known copyright restrictions in 
the United States on the use of the text. 






J. L. E. DREYER, Ph.D., F.R.A.S. 








PH.D., r.E.S.E., &C., 

irbia ffioof? is DcO IcateS 




Astronomers are so frequently obliged to recur to observa- 
tions made during former ages for the purpose of supporting 
the results of the observations of the present day, that there 
is a special inducement for them to study the historical 
development of their science. Much labour has accordingly 
been spent on the study of the history of astronomy, and in 
particular the progress of the science in the sixteenth and 
seventeenth centuries has of late years formed the subject of 
many important monographs. The life of Copernicus has 
been written in considerable detail by Prowe, Hipler, and 
others. Of Kepler's numerous works we owe a complete 
edition to the patient industry and profound learning of the 
late Dr. Frisch of Stuttgart, while the life of Galileo, and 
particularly his persecution and trial, have called forth quite 
a library of books and essays. In the present volume I 
have attempted to add another link to the chain of works 
illustrating the birth of modern astronomy, by reviewing 
the life and work of Tycho Brahe, the reformer of observa- 
tional astronomy. 

Although not a few monographs have been published 
from time to time to elucidate various phases in the career of 
Tycho Brahe, while several popular accounts of his life (by 
Helfrecht, Brewster, &c.) have appeared, the only scientific 

viii PKEFACE. 

biography hitherto published is that of Gassendi. This 
writer obtained valuable materials from some of Tycho 
Brahe's pupils, and from the Danish savant Worm, but he 
chiefly derived his information from a close scrutiny of 
Tycho's own writings, never failing to make use of any 
particulars of a biographical nature which might be recorded 
in passing by Tycho. In studying Tycho's works, I have 
repeatedly come across small historical notes in places where 
nobody would look for such, only to find that Gassendi had 
already noticed them. In 1745 a biography was published 
in a Danish journal (Bang's Samlinger, vol. ii.), the contents 
of which are chiefly taken from Gassendi, but which also 
contains a few documents of interest. Of far greater im- 
portance is a collection of letters, royal decrees, and other 
documents, published in 1746 by the Danish historian Lan- 
gebek in the Danske Magazin, vol. ii., which stiU remains 
the principal source for Tycho's life. A German translation 
of this and the memoir in Bang's Samlinger was published 
in 1 7 5 6 by Mengel, a bookseller in Copenhagen, who wrote 
under the high-flown pseudonym Philander von der Wei- 
stritz ; and as his book has naturally become more generally 
known than the Danish originals, I have, when quoting 
these, added references to Weistritz's book. During the 
present century several Danish historians have brought to 
light many details bearing on Tycho's life which will be 
referred to in this volume; and in 1871 a Danish author, 
P. R. Priis, published a popular biography in which were 
given various hitherto unpublished particulars, especially 
of Tycho's beneficiary grants and other endowments. The 
same writer has also published a number of letters ex- 
changed between Tycho and his relations, and various con- 
temporary astronomers. Of great scientific interest is the 
correspondence between Tycho and Magini, published and 


commented by Professor Pavaro of Bologna with the care 
and learning by which the writings of tbis author are 
always distinguished. Some other letters from the last 
years of Tycho's life have recently been published by Pro- 
fessor Burckhardt of Basle. Lastly, we must mention the 
meteorological diary kept at Uraniborg, which is of great 
historical value as affording many interesting glimpses of 
Tycho Brahe's home life. It was published in 1876 by 
the Eoyal Danish Society of Science. 

Among other publications of importance for the study 
of Tycho Brahe's life and activity must .be mentioned the 
biography of Kepler, by Frisch, in the last volume o£ 
Kepler's Opera Omnia, and several papers by Professor 
Eudolph Wolf of Zurich on Landgrave Wilhelm of Hesse- 
Oassel, and his astronomers Eothmann and Biirgi. Though 
only indirectly bearing on Tycho (of whose merits Professor 
Wolf on every occasion speaks somewhat slightingly), these 
valuable papers throw much light on the state of science at 
the end of the sixteenth century, and will often be found 
quoted in the following pages. 

Having for many years felt specially interested in Tycho 
Brahe, it appeared to me that it would be a useful under- 
taking to apply the considerable biographical materials 
scattered in many different places to the preparation of a 
biography which should not only narrate the various inci- 
dents in the life of the great astronomer in some detail, but 
also describe his relations with contemporary men of science, 
and review his scientific labours in their connection with 
those of previous astronomers. The historical works of 
Montucla, Bailly, Delambre, and Wolf have indeed treated 
of the astronomical researches of Tycho Brahe, but as the 
plans of these valuable works were different from that 
adopted by me, I believe the scientific part of the present 


volume will not be found superfluous, particularly as it is 
founded on an independent study of Tycho's bulky works. 
To these I have given full references for every subject, so 
that any reader may find further particulars for himself 
without a laborious search. Many details, especially as to 
the historical sequence of Tycho's researches, have been 
taken from his original MS. observations in the Royal 
Library at Copenhagen, which I was enabled to examine 
during two visits to Copenhagen in 1888 and 1889. On 
the same occasions I also studied three astrological MSS. 
of Tycho's, of which an account will be found in Chap- 
ter VI. It may possibly be thought by some readers that 
I have devoted too much space to the consideration of 
the astrological fancies of the Middle Ages. But my 
object throughout has been to give a faithful picture of the 
science of the sixteenth century, and for this purpose it is 
impossible to gloss over or shut our eyes to the errors of 
the time, just as it would be absurd, when writing the 
scientific history of other periods, to keep silence as to the 
phlogistic theory of combustion, the emission theory of 
light, or the idea of the sun as having a solid nucleus. If 
the study of the history of science is to teach us anything, 
we must make ourselves acquainted with the by-paths and 
blind alleys into which our forefathers strayed in their 
search for truth, as well as with the tracks by which they 
advanced science to the position in which our own time 
finds it. 

With the exception of the astronomical manuscripts in 
the Royal Library at Copenhagen (for facilities in using 
which I was indebted to Dr. Bruun, chief librarian), I have 
not made use of any unpublished materials ; but the scanty 
harvest reaped by modern searchers makes it extremely 
unlikely that anything of importance remains to be found 


among unpublished sources. I believe, however, that certain 
periods of Tycho Brahe's life in this volume will be found 
to appear in a light somewhat different from that in which 
previous writers have seen it. Especially it seems difficult 
to deny that Tycho's exile was almost entirely due to him- 
self, and that there was no absolute necessity for his leaving 
Hveen, even though he had lost most of his endowments. 
As an amusing instance of the manner in which many inci- 
dents have been misunderstood by those who consider Tycho 
a martyr of science, we may mention that the trouble into 
which the minister of Hveen got with his superiors and 
with his parishioners (for his unwarranted interference with 
the Church ritual), has been described as a riot or fight, 
instigated by a wicked statesman, in which Tycho's shepherd 
or steward (pastor !) was injured. 

I should scarcely have been able to write this book far 
from great libraries if I had not for many years taken every 
opportunity of acquiring books or pamphlets bearing in any 
way on the subject, or of making excerpts from such as 
could not be purchased. I have, however, been under great 
obligations to the Astronomer Royal for Scotland, who most 
kindly allowed me to consult the literary treasures on the 
star of 1572 in the Crawford Library of the Eoyal Observa- 
tory, Edinburgh. Hereby I have been enabled to examine 
even some writings on the new star which were unknown 
to Tycho Brahe. 

That I have adopted the Latin form of the astronomer's 
name, by which he is universally known, instead of his real 
baptismal name of Tyge, scarcely requires an apology. It 
would indeed only be affectation to speak of Schwarzerd or 
Koppemigk instead of Melanchthon or Copernicus. The 
portrait of Tycho Brahe in this volume (about which see 
p. 264) has already appeared in Woodburytype in the 


Memoirs of the Literary and Philosophical Society of 
Manchester, vol. vi., and in woodcut in Nature, vol. xv. 
Most of the other illustrations are taken from Tycho'a own 
works. For photographs, from which the illustrations in 
Chapter XI. were made, I am indebted to Professor Safarik 
of Prague, who has also kindly communicated various par- 
ticulars about Tycho's life in Bohemia. 


The Obsbrvatort, Armagh, 
September iSgo. 




Kevival of science in Germany — Purbach. — Greek astronomy 
studied — Eegiomontanus — Ephemerides — Walther — Apianus 
— Coj)ernicns — New system of tie world proposed — State of 
astronomy in the sixteenth century i 



Family — Cliildhood — At Copenhagen University — Becomes in- 
terested in astronomy — Sent to Leipzig — Commences to 
take observations — Returns home — Stay at Wittenberg — ■ 
At Eostock — At Augsburg — Construction of a large quadrant 
— Resides at Heridsvad — Chemical studies . . . . lo 



First appearance — Tyoho's observations — His book on the star — 
His calendar for 1573 — Other observations of the star — 
Measurements — Moment of first appearance — Opinion as to 
nature of star — Alleged earlier appearances of new stars — 
Its supposed significance 38 


TRA VELS IN 1575. 

Tycho's wife and children — Oration on astrology — Travels in 
Germany^Landgrave Wilhelm IV. — King Frederick II. — 
Island of Hveen granted to Tycho— Pension . . . .70 





Description of Hveen— Local traditions —^Uraniborg — Instru- 
, nients— Stjerneborg Observatory— Grant of KuUagaard manor 
—Prebend of Roskilde— Nordfjord estate in Norway . . 88 



Home life — Printing press — Tenants at Hveen — Students and 
assistants — Flemlose — Wittich — Elias Olsen — Longomon- 
tanus — Chemical researches — Correspondence — Visitors — 
Relations witb the King — Horoscopes of Princes^Tycbo's 
opinion of judicial astrology — Death of the King . . .114 



Comet of 1577 — Six other comets — Tycho's book on comet of 1577 
— Comets celestial objects — ^Tychonic system of the world — 
~ System of Copernicus yet incomplete — Eeymers (Ursus) and 
his system 158 


Tycho's larger book on the star — Its great distance — Dimensions 

of the universe — Nature of star — Its astrological eflfect . 186 



New Government — New grant to Tycho — House at Copenhagen — 
Sophia Brahe — Visit of James VI. — Visit of Rothmann — 
Correspondence with the Landgrave and Magini — Visit of 
the young King — Tycho's quarrel with a tenant — Neglects to 
repair chapel of his prebend — Quarrel with Gellius — Volume 
of Epistles — Accession of King Christian IV. — Tycho de- 
prived of Norwegian fief — Valkendorf — Pension stopped 

Tycho leaves Hveen — Troubles about clergyman at Hveen 108 





Tycho at Copenhagen — Departs for Eostock — Letter to the King 
— Lends money to the Dukes of Mecklenhurg — The King's 
reply — Tycho at Wandsbeck — Vain attempts to reconcile the 
King— Publishes description of instruments — Star catalogue 
— Calumnies of Reymers — Invitation from the Emperor — 
Tycho winters at Wittenberg 239 



Rudolph 11. — Tycho's salary — Castle of Benatky — Financial 
difB.culties — Work resumed— Kepler's youth — His arrival at 
Benatky and quarrel with Tycho — Reconciliation — Tycho 
settles at Prague — His assistants — Solar and lunar theory — 
Tycho's death and funeral . . . . . . . 277 


Zodiacal and equatorial armillse — Meridian quadrant — Altazi- 
muth quadrant — Time determinations — Sextants for distance 
. measures — Subdivision of arcs — Nonius — Transversal 
divisions — Improved pinnules — Theory of sun's motion — Re- 
fraction — Lunar theory — Discovery of lunar inequalities — 
Kepler and the annual equation — Motion of planets — Posi- 
tions of fixed stars — Absolute longitude — Star catalogue — 
Precession — Trepidation disproved — Accuracy of observations 
— Alleged error of Tycho's meridian — Trigonometrical 
formulae 315 


Pate of Tycho's instruments — His family in Bohemia — Publica- 
tion of his books — Tycho's manuscript observations — Hveen 
after Tycho's time 365 



Specimen of Tycho's early observations with the cross-staflE— List 
of Tycho Brahe's pupils and assistants— Tyoho's opinion 
about astrological forecasts— Kepler's account of Tycho Brahe's 
last illness-^Comparison of Tycho Brahe's positions of stan- 
dard stars with modern results-^On the alleged error of 
Tycho's meridian line— Huet's account of the state of Hveen 
in 1652- Catalogue of the volumes of manuscript observa- 
tions of Tycho Brahe in the Koyal Library, Copenhagen — 
Bibliographical Summary 381 


Portrait of Tycho Beahb Frontispiece 

Moral Quadrant To face p. loi 

Castle of Bbnatky ,,282 

Ferdinand I.'s Villa ,,298 

Ttcho's Tombstone ,,311 

(The above by S. B. BOIAS & Co., London.) 


Page 54, last line, for "Locus in Sagit.," read " Locus © in Sagit." 
„ 66, Footnote 2, line 7 from end, add : That Hardeok speaks of the 
comet of 1264, although he gives the year 1260, may be seen 
from his references to Pope Clement IV. (1265-1268) and the 
battle of Benevent (1266). According to Pingr4 several writers 
have been confused with regard to the year of this comet. 
„ 127, hne 2, for " Coll," read " Crol." 



The early part of tlie sixteenth, century must always rank 
among the most remarkable periods in the history of 
civilisation. The invention of printing had made literature 
the property of many to whom it had hitherto been in- 
accessible, and the downfall of the Byzantine Empire had 
scattered over Europe a number of fugitive Greeks, who 
carried with them many treasures of classical literature 
hitherto unknown in the Western world, while Eaphael, 
Michael Angelo, and other contemporaries of Leo X. revived 
the glory of the ancients in the realm of art. The narrow 
limits of the old world had vanished, and the Portuguese 
and Spanish navigators had led the way to boundless fields 
for human enterprise, while the Reformation revolutionised 
the spirit of mankind and put an end to the age of ignorance 
and superstition. 

During this active period there were also signs of renewed 
vigour among the devotees of science, and the time was 
particularly favourable to a revival of astronomical studies. 
Students of astronomy were now enabled to study the 
Greek authors in the original language, instead of having 
to be content with Latin reproductions of Arabian transla- 
tions from the Greek, which, through the Italian Univer- 



sities, Had been introduced into Europe during the Middle 
Ages. Another impulse was given by tlie voyages of 
discovery, as navigators were obliged to trust entirely to 
the stars and the compass, and therefore required as perfect 
a theory as possible of the motions of the heavenly bodies. 
We see accordingly at the end of the fifteenth century 
and the beginning of the sixteenth considerable stir in the 
camp of science, but as yet only in Germany — a circumstance 
not difficult to explain. Though divided into a great 
number of semi-independent states, Germany bore still the 
proud name of the Holy Eoman Empire, and on account of 
the claims represented by this name the Germans had for a 
long time been in constant intercourse with Italy, the land 
with the great past, and still, notwithstanding its political 
misery, the leader of civilisation. . It was an intercourse of a 
peaceful and commercial as well as of a warlike character; 
but in both ways was this of benefit to the Germans, pro- 
ducing among them much knowledge of foreign affairs, and 
giving them greater facilities for taking up the scientific 
work of the ancients than were found in other parts of 

The first astronomer of note was Georg Purbach (1423- 
1461), who studied at the University of Vienna, and 
afterwards for some time in Italy, His principal work 
on astronomy {Theoricce Novcb Planetarum) attempted to 
develop the old hypothesis of material celestial spheres, 
and was but a mixture of Aristotelean cosmology and 
Ptolemean geometry ; but he was the first European to 
make use of trigonometry, the principal legacy which 
astronomers owe to the Arabs. Purbach endeavoured to 
get beyond the rudiments of spherical astronomy, which 
hitherto had formed the only subject for astronomical 
lectures, and had been taught through the medium of a 
treatise written in the thirteenth century by John Holy- 


wood (JoHanues de Sacrobosco) for use in the University of 
Paris. WMle lecturing at Vienna, Purbacli's attention was 
drawn to a young disciple of great promise, Johann Miiller, 
from Konigsberg, a small village in Pranconia, wHere he 
had been born in 1436. He is generally known by the 
name of Regiomontanus, though he does not seem to have 
used this name himself, but always that of Johannes de 
Monteregio. He entered heart and soul into his teacher's 
studies of the great work of Ptolemy, which embodied all 
the results of Greek astronomy, and the talented pupil soon 
became an invaluable co-operator to Purbach. They did 
not confine themselves to theoretical studies, but, with such 
crude instruments as they could construct, they convinced 
themselves of the fact that the places of the planets 
computed from the astronomical tables of King Alphonso X. 
of Castile differed very considerably from the actual posi- 
tions of the planets in the sky.''- In the midst of these 
occupations the two astronomers had the good luck to 
become acquainted with a man who was well qualified 
to help them to carry out their greatest wishes. This 
man was Cardinal Bessarion, a Greek by birth, who, as 
Bishop of Nicsea, had accompanied the Byzantine Emperor 
on his journey to the Council of Perrara in 1438, where 
he tried to bring about a reconciliation between the Greek 
and Roman Churches. Bessarion remained in Italy and 
joined the Roman Church, but he never forgot his old 
country, and contributed very much to make the classical 
Greek literature known in the West. The translation of 
the original Almagest (as Ptolemy's work was generally 
called, from a corruption of the Arabic Al megist, in its 

^ The Tabulaa Alphonsins had been computed in the middle of the 
thirteenth century by a number of Arabian and Jewish astronomers under 
the personal direction of King Alphonso el Sabio. They were founded on 
the theory of Ptolemy and the observations of the Arabs, and were first 
printed, at Venice in 1483. 


turn derived from fji.eyi<TTtj avvTa^i's) was a subject in which 
lie was particularly interested, and during Ms stay at 
Vienna as Papal Nuncio he succeeded in communicating to 
Purbach his own anxiety to make Ptolemy better known in 
the scientific world. Purbach was on the point of starting 
for Italy for the purpose of collecting Greek manuscripts, 
when he died suddenly in 1461, but Eegiomontanus suc- 
ceeded to his place in the Cardinal's friendship, and set out 
for Italy with Bessarion in the following year. 

Eegiomontanus stayed about seven years in Italy, visit- 
ing the principal cities, and losing no chance of studying 
the Greek language and collecting Greek manuscripts. At 
Venice he wrote a treatise on trigonometry, which branch 
of mathematics he also, during the remainder of his life, 
continued to develop, so that he constructed a table of 
tangents (tabula, fecionda), and probably only was prevented 
by his early death from completing his treatise by intro- 
ducing the use of tangents therein.i After his return to 
Germany, he settled, in 1471, at Niirnberg. This city was 
one of the chief centres of German industry and literary 
life, and no other German city had such regular commercial 
communication with Italy, from whence the produce of the 
East was brought into the market, and nowhere did the 
higher classes of citizens use their wealth so willingly in 
support of art and science. The new art of printing had 
recently been introduced at Niirnberg, where a regular 
printing-press was now working — a circumstance of parti- 
cular importance to the collector of Greek writings. A 
wealthy citizen, Bemhard Walther (born 1430, died 1504), 
became at once the friend and disciple of Eegiomontanus, 

The treatise De Triangulis Omnimodis, libri v., was first published at 
Niirnberg in 1533, while Regiomontanus himself printed the Tabvlce Diree- 
tionwm in 1475, containing both a table of sines for every minute and the 
above-mentioned table of tangents for every degree, extended to every 
minute by Reinhold in a new edition in 1554. 


and arranged an observatory for tteir joint use. Instru- 
ments, as fine as the skilful artisans of Niirnberg could 
make them, adorned tke earliest of European observatories, 
and the two friends made good use of tkem (they observed 
already the comet of 1472), and originated several new 
methods of observing. But Eegiomontanus did not forget 
the printing operations, and published not only Purbach's 
TheoriccB Novae and trigonometrical tables, but also his own 
celebrated Ephemerides, the first of their kind, which, some 
years afterwards, were made known to the navigators 
through the German geographer Martin Behaim, and 
guided Diaz, Columbus, Vasco de Gama, and many others 
safely across the ocean. Nothing spread the fame of the 
astronomer like these Ephemerides, and the Pope was thus 
induced to invite Eegiomontanus to Rome to reform the 
confused calendar. The invitation was obeyed in 147S, 
but Eegiomontanus died in July 1476 very suddenly 
at Eome. He only reached the age of forty, and no 
doubt much might have been expected from him if death 
had not so early stopped his career ; but he had rendered 
great service to science, not only by his endeavours to save 
the Greek authors from oblivion,^ but by his Ephemerides, 
his development of trigonometry, and his observations. 
Walther survived him twenty-eight years, and continued 
his observations, which were published in 1544. 

By Purbach and Eegiomontanus the astronomy of the 
Alexandrian school had been introduced at the German 
Universities, and the increased demands which navigators 
made on astronomers continued to help forward the study 
of astronomy in Germany, which country, by having a 
sovereign in common with Spain, for a while had much 
intercourse with the latter country. Of the astronomers 

' The Greek text of Ptolemy's work from the MS. brought home by 
Regiomontanus was published at Bale in 1538. 


wlio worked during the first half of the sixteenth century 
we shall here mention Peter Apianus or Bienewitz, who 
taught at the University of Ingolstadt. Besides other 
works, he published in 1540 a large book, Astronomicum 
Ccesareum, dedicated to Charles the Fifth. In this beau- 
tiful volume the author represented, by means of movable 
circles of cardboard of various colours, the epicyclical motions 
of the planets according to the Ptolemean system, and ex- 
pected to be able in this way to find their positions without 
computation. The book was received with much applause, 
and is really in some ways to be admired, though one cannot 
help agreeing with Kepler in regretting the " miserable 
industry " of Apianus, which after all only produced a very 
rough approximation to the real motions of the stars, but 
which is eminently characteristic of the low state of science 
at that time. Apianus deserves more thanks for having 
paid much attention to comets, and for having discovered 
the important fact that the tails of these bodies are turned 
away from the sun. This was also pointed out about the 
same time by Fracastoro of Verona in a work published in 
1538^ containing an elaborate attempt to revive the theory 
of concentric spheres of Eudoxus, which had been pushed 
into the background by the Ptolemean system of the world. 
Only three years after Apian's volume appeared the great 
work of Mcolaus Copernicus, Be Mevolutionibus (1543), 
which was destined to become the corner-stone of modern 
astronomy. We shall in the following so often have occasion 
to refer to the labours of this great man, that a few words 
will suffice in this place. Copernicus, who not only dis- 
covered the greatest truth in astronomy, but who even by his 
opponents was admitted to be an astronomer worthy of being 
classed with Hipparchus and Ptolemy, was born in 1473 at 
Thorn, on the Vistula, a town which belonged to the Hansa 
League, and a few years before had come under the suzerainty 


of Poland. He studied first at tHe University of Krakau, 
where astronomy was specially cultivated, and at the age of 
twenty-four he proceeded to Bologna, where he enjoyed 
the teaching of Domenico Maria Novara. Thus Copernicus 
not only became acquainted with Ptolemy's work, but also 
acquired some familiarity with the astrolabe or astronomical 
circle, one of the few crude instruments then in use. From 
about the end of 1505 till his death in 1543, Copernicus 
lived in the diocese of Ermland, in Prussia, most of the 
time in the town of Frauenburg, where he held a canonry 
at the cathedral. It is much to be regretted that we are 
utterly unacquainted with the manner in which Copernicus 
came to design the new system of astronomy which has 
made his name immortal. But he had probably early per- 
ceived that, however valuable the labours of Eegiomontanus 
had been, they had not improved the theory of celestial 
motion, so that the most important problem, that of com- 
puting beforehand the positions of the planets and account- 
ing for their apparently intricate movements, was practically 
untouched since the days of Ptolemy. That great mathe- 
matician had completed and extended the planetary system 
of Hipparchus, and had in a wonderfully ingenious manner 
represented the complicated phenomena. But more than 
1400 years had elapsed since his time, and the system, 
however perfect from a mathematical point of view, had 
long been felt to be too complicated, and not agreeing 
closely enough with the observed movements of the 
planets. This circumstance led Copernicus to attempt the 
construction of a new system, founded on the idea that the 
sun, and not the earth, is the ruler of the planets. But 
though Copernicus on the basis of this idea developed a 
theory of the planetary movements as complete as that of 
Ptolemy, he was unable to do more than to demonstrate the 
possibility of explaining the phenomena by starting from 


the heliocentric idea. Having no materials from winch to 
deduce the true laws of the motion of the planets in elliptic 
orbits, he was obliged to make use of the excentric circles 
and epicycles of the ancients, by which he greatly marred 
the beauty and simplicity of his system.^ He did not 
possess accurate instruments, and took but few observations 
with those he had. The idea does not seem to have struck 
him that it was indispensable to follow the planets through 
a number of years with carefully constructed instruments, 
and that only in that way could the true theory of planetary 
motion be found. 

There was much to be done yet ere the reform of astro- 
nomy could be accomplished. The pressing want of new 
tables to take the place of the antiquated Alphonsine tables 
was supplied a few years after the death of Copernicus by 
Erasmus Eeinhold, but though the positions of the planets 
could be computed from them with greater accuracy than 
from the old tables, the " Prutenic tables " (published in 
1551) did not by this superiority oifer any proof of the 
actual truth of the Copemican principle. 

A century had now elapsed since the study of astronomy 
had commenced to revive in Italy and Germany, but as 
yet the work accomplished had chiefly been of a tentative 
and preparatory kind, Copernicus alone having attempted 
to make science advance along a new path. Still, much 
useful work had been done. The labours of the ahtsients 
had now become accessible in the originals ; the Araos and 
Regiomontanus had developed trigonometry, and thereby 
greatly facilitated astronomical computations; Copernicus 
had shaken the implicit conviction of the necessity of 
clinging to the complicated Ptolemean system, and had 
offered the world an alternative and simpler system, while 
new tables had been computed to take the place of the 

' We shall return to this subject in Chapter VII. 


Alphonsine tables. But otherwise the astronomy of the 
ancients reigned undisturbed. No advance had been made 
in the knowledge of the positions of the fixed stars, those 
stations in the sky by means of which the motions of the 
planets had to be followed; the value of almost every 
astronomical quantity had to be borrowed from Ptolemy, 
if we except a few which had been redetermined by the 
Arabs. No advance had been made in the knowledge of 
the moon's motion, so important for navigation, nor in the 
knowledge of the nature of the planetary orbits, the uniform 
circular motion being still thought not only the most per- 
fect, but also the only possible one for the planets to pursue. 
Whether people believed the planets to move round the earth 
or round the sun, the complicated machinery of the ancients 
had to be employed in computing their motions, and crude 
as the instruments in use were, they were more than suffi- 
cient to show that the best planetary tables could not fore- 
tell the positions of the planets with anythiag like the 
desirable accuracy. 

No astronomer had yet made up his mdnd to take nothing 
for granted on the authority of the ancients, but to deter- 
mine everything himself. Nobody had perceived that the 
answers to the many questions which were perplexing 
astronomers could only be given by the heavens, but that 
the answers would be forthcoming only if the heavens were 
properly interrogated by means of improved instruments, 
capable of determining every astronomical quantity anew by 
systematic observations. The necessity of doing this was 
at an early age perceived by Tycho Brahe, whose life and 
work we' shall endeavour to sketch in the following pages. 
By his labours he supplied a sure foundation for modern 
astronomy, and gave his great successor, Kepler, the means 
of completing the work commenced by Copernicus. 


Tycho Bkahe belonged to an ancient noble family wHch 
had for centuries flourisbed not only in Denmark, but also 
in Sweden, to wbich country it had spread in the fourteenth 
century, when one of its members, Torkil Brahe, fled thither 
from Denmark to escape punishment for manslaughter. The 
family still exists in both countries. In the sixteenth cen- 
tury the Danish nobility was still of purely national origin, 
unmingled with the foreign blood which became merged ia 
it in the course of the next two hundred years, when every 
new royal bride brought with her a train of needy adven- 
turers, with empty purses and long titles, from the Holy 
Roman Empire. Like their foreign fellow-nobles, they were 
descended from men who had received grants of land on 
tenure of military service, and until about the end of the 
thirteenth century they can hardly be said to have formed 
a separate class, as their privileges and duties were, not yet 
of necessity hereditary. They were untitled (till 1671), 
but all the same they were as proud and jealous of the 
privileges of their order as any Norman count or baron, and 
were called by the characteristic names of " free and well- 
born" or " good men." In the first half of the sixteenth 
century they had successfully resisted the attempts of King 
Christiern II. to curb their power, and had driven him from 
his throne ; and when the lower orders afterwards had 

attempted to replace him on the throne rendered vacant 



by tlie death of Ms brother and successor, the nobles had, 
after a hard struggle, crushed their opponents, though the 
latter were backed by the powerful Hansa city of Liibeck. 
The Eeformation had broken the rival power of the Church, 
and the nobles had in consequence (though not to the same 
extent as in Germany and England) increased in wealth and 
possessions. And during the next fifty years they did not 
abuse their worldly advantages, but were, as a rule, faithful 
servants of their king and country, generous and kind to 
their tenants, fond of studies and learning. Most of them 
had in their youth travelled abroad, frequently for years at 
a time, and studied at foreign universities, where they 
acquired knowledge not only of books, but also of the 
world. At their country-seats many of them encouraged ' 
and protected men of learning, and kept up their acquaint- 
ance with classical literature, as well as with the more 
humble folk-lore which, in the shape of old epics and 
ballads {Kjcempeviser), had been handed down from one 
gene]:ation to another among the humble as well as 
among the high-bom. Almost every country-seat pos- 
sessed what was at that time considered a fine library, 
so that it was quite natural that hardly a pamphlet or 
book was published without a dedication to some noble 

The father of the great astronomer was Otto Brahe, born 
in 1517, from 1562 or 1563 a Privy Councillor, and 
successively lieutenant of various counties, finally governor 
of Helsingborg Castle (opposite Blsinore), where he died 
in 1571. His wife was Beate Bille, whom he had mar- 
ried in I 5 44, and their second child and eldest son, Tyge, 
was born on the 14th December 1546 at the family seat 
of Knudstrup, in Scania or Skaane, the most southern pro- 
vince of the Scandinavian peninsula, which at that time 
still belonged to Denmark, as it had done from time 


immemorial.^ Tyge, or Tycko (as he afterwards Latinised 
bis name), had a still-born twin-brother, a fact alluded to 
in a Latin poem which he wrote and had printed in 1572.^ 
Otto Brahe had in all fiye sons and five daughters (in 
addition to the still-born son), the youngest being Sophia, 
born in 1556, who will often be mentioned in the sequel. 
Though he was the eldest son and heir to the family 
estate of Eoiudstrup, Tycho did not remain under his 
father's care for more than about a year, as his father's 
brother, Jorgen (George) Brahe, who was childless, had been 
promised by Otto, that if the latter got a son, he would let 
Jorgen bring him up as his own. The fulfilment of the 
promise was claimed in vain ; but Jorgen Brahe was not to 
be put off so easily, and as soon as a second boy had been 
bom to Otto, the uncle coolly carried ofi" his eldest nephew 
by stealth as soon as he got an opportunity. The parents 
of Tycho gave way when the thing was done, knowing that 
the child was in good hands, and doubtless expecting that 
the foster-parents would eventually leave their adopted son 
some of their wealth, which they also seem to have done. 

We know nothing of Tycho's childhood except that he 
was brought up at his uncle's seat of Tostrup, and was 
from the age of seven taught Latin and other rudiments of 
learning by a tutor.^ He acquired the necessary familiarity 
with the only language which was then properly studied, so 
that he was afterwards able not only to converse in and 
write Latin, but also to write poetry in this language, 
which was then and for a long time afterwards considered 
a very desirable accomplishment for a learned man. We 
shall often have occasion to quote his poetry, some of which 

'■ In several places in his writings Tycho alludes to the 13th December as 
his birthday, but this is astronomically speaking, counting the day from noon, 
as he was born between nine and ten o'clock in the morning. 

' Reprinted in Danskc Magazin, ii. p. 170 (Weistritz, ii. p. 23). 

' Autobiographical note, Astron. Inst. Mechanica, fol. G. 


is not wittiout merit. Thus prepared, lie was sent to 
Copenliagen in April 1559 to study at the University- 
there.'^ This seat of learning had been founded in the year 
1 479 ^y permission of the Pope, but it had languished for 
a number of years for want of money and good teachers. 
The confiscation of the property of the monasteries enabled 
King Christian III. to commence improving it, and by the 
statutes of 1539 (which were still in force in Tycho 
Brahe's time) the number of professors was fixed at fourteen, 
three of Divinity, one of Law, two of Medicine, and eight 
in the Faculty of Arts, among whom were several whose 
names were honourably known outside their own country. 
Tycho now commenced his studies here, devoting himself 
specially to rhetorics and philosophy, as being the branches 
of learning most necessary to the career of a statesman, for 
which he was destined by his uncle, and probably also by 
his father, who .had at first objected to his receiving a 
classical education.^ But astronomy very soon claimed his 
attention. On the 21st of August 1560 an eclipse of 
the sun took place, which was total in Portugal, and of 
which Clavius has left us a gi-aphic description. Though 
it was only a small eclipse at Copenhagen, it attracted the 
special attention of the youthful student, who had already 
begun to take some interest in the astrological predictions 
or horoscopes which in those days formed daily topics of 
conversation. When he saw the eclipse take place at the 
predicted time, it struck him " as something divine that 
men could know the motions of the stars so accurately that 

^ In tliose days students frequently entered a university at a very early age, 
and witli an exceedingly slender stock of knowledge. At Wittenberg one of 
the professors in the faculty of Arts was bound to teach the junior students 
Latin grammar, and one of the Wittenberg professors in his opening address 
pointed out how simple the rudiments of arithmetic were, and how even 
multiplication and division might be learned with some diligence. Prowe, 
Nic. Coppernicus, i. p. 116 

2 Gassendi, p. 4. 


they could long before foretell tHeir places and relative 
positions." ^ He therefore lost no time in procuring a copy 
of the Ephemerides of Stadius in order to satisfy his 
curiosity as to astronomical matters ; and not content with 
the meagre information he could get from this book, he 
very soon made up his mind to go to the fountain-head, 
and at .the end of November in the same year he invested 
two Joachims-thaler in a copy of the works of Ptolemy, 
published at Basle in 1551. This copy is stiU in existence, 
and may be seen in the University Library at Prague ; there 
are many marginal notes in it, and at the bottom of the 
title-page is written in Tycho's own hand that he had 
bought the book at Copenhagen on the last day of Novem- 
ber for two thaler. This book contained a Latin translation 
of all the writings of Ptolemy except the Geography, the 
Almegist being in the translation of Georgios from Tre- 
bizond. The study of this complete compendium of the 
astronomy of the day must have given the youthful student 
enough to do ; indeed, it may well be doubtful whether he 
was at that time able to master it. 

Tycho remained at Copenhagen for three years, chiefly 
occupying himself with mathematical and astronomical 
studies. We are not acquainted with any details as to 
this period of his life; all we know is that he formed an 
intimate friendship with one of the professors of medicine, 
Hans Frandsen, from Ribe, in Jutland (Johannes Francisci 
Ripensis), and especially with Johannes Pratensis, a young 
man of French esti-action, who also afterwards became 
professor of medicine.^ Jorgen Brahe now thought that 
the time had come to send his nephew to a foreign uni- 

' Gassendi, p. 5. 

- His father waa Philip du Pr^, from Normandy, who had come to Den- 
mark with Queen Isabella, the wife of Christiern II. He afterwards became 
a Protestant and Canon of Aarhus Cathedral. N. M. Petersen, Den Damke 
Literatiirs Uisorie, iii. p. 190. 


versity, as was tten customary. He probably Hoped tbat, 
wten removed from his friends at Copenhagen, the young 
worshipper of Urania might be induced to give up his 
scientific inclinations and devote himself more to studies 
which would in after years enable him to take the place 
in his native land to which his birth entitled him. The 
university he selected for his nephew was that of Leipzig. 
During the thirteenth and fourteenth centuries Danish 
students had followed the universal custom of the age and 
repaired to the University of Paris, where several of them 
had risen to great distinction, and even occupied the 
rectorial chair;-' but gradually as the German universities 
improved they became more frequented by Danes than 
Paris. To accompany Tycho as tutor, Jorgen Brahe chose a 
young man of great promise, who, although only four years 
older than his pupil, was known to be steady enough to be 
intrusted with this responsible office. Anders Sorensen 
Vedel, son of a respected citizen of YeUe, ia Jutland, had 
been less than a year at the University, where he attended 
lectures on divinity, and at the same time devoted him- 
self to the study of history. He became afterwards Eoyal 
Historiographer, and is particularly known by his translation 
of the Latin Chronicle of Saxo Grammaticus, an important 
source of Danish history from the end of the twelfth 
century, and also by his edition of the ancient national 
ballads or Kjaempeviser.^ Vedel was only too happy to 
accept the proposal of accompanying the young nobleman 
abroad, as there was at that time no Professor of History 

^ There were four times in the fourteenth century Danish Rectors of the 
TTniversity of Paris (N. M. Petersen, Den Danslce Literafurs Uistorie, i. 
p. 74). Students from Denmark, Sweden, and Norway (provincia Dacise) 
belonged to Anglicana Natio, one of the four Nations of the University. 

^ IJistoriske Eflerretninger om Anders Sorensen Vedel, af C. F. Wegener. 
Appendix to a new edition of Ben Danslce Kronike af Saxo Grammaticus, 
translated by Vedel, Copenhagen, 1851, fol. This book is a Taluable source 
for Tyoho's early life. 


ill the Copenhagen University, while it was not uncommon 
to find professors in German universities who combined the 
chair of History with some other one.^ 

Vedel and his pupil left Copenhagen on the 1 4th February 
I 562, and arrived at Leipzig on the 24lh ]\riirch fnUowiiiji;. 
They were at once installed in the house of one of the pro- 
fessors," possibly on the recommendation of some of tlieii- 
learned friends in Copenhagen, several of whom were in 
constant communication with their colleii,gues at the Leipzig 
University. They had at once (heir naiuos entered in the 
book of matriculation, whore they may still be seen as 
"Andreas Severinus Cimber" and " Tyho Brade ex Soan- 
dria." There is, however, no sign whatever that Tycho 
devoted himself to the study of law, while wo know that he 
at once sought the acquaintance of ilio professor of mathe- 
matics, Johaimes Homilius ; of his disciple, Bartholomasus 
Scultetus (Schultz), and probably also of the "electoral 
mathematician," Valentine Thau." lloiiiilius died on Die 
Sth July, a little over throe months al'ter Tycho's arrival, 
but we shall afterwards see that ho had even in that 
short time imparted valuable and practical knowledge to 
the young student. Vediil did his best to carry out his 
instructions by trying to keep Tycho to tlio study of jiiri.s- 
pruiTence, but Tycho would not allow himself to be hinditred 
in his favourite pursuits, and spent juosI, of his money on 

1 Though tho University of Luip/.ij,' did not got a chair of History till :S79, 
Oamerariua (about whom see next I'Mgii) wfts to nciino oxtont oonsidorod ft« 
being Profc^Bsor of 1 1 iHlory, and is oven onoo styled " ilibtoriarum ot utriusqua 
lirij^iiu! priifcHHor " (Wi'(;oncr, I.e., p. 31). 

' II in name is not laiown. Tyolio only nmnlionH him onoo In a nolo 
aiiiDiiK his observations : " 1564, 14th Deo,— Sub coanam I'lnlliKiiniH, qui iqiml 
doctoroni nostrum hospitem convivabatur, dicebat . , ." (tlioii (ollowa uu 
account nf tho couvurHjition in (Jurniun), 

' Tliau is niniiliooi'd by VihIhI as a fiiund of his own, and iiiipcMin to liava 
been tlio iiu'c'iitor of an artificial car (rliitda, vianuiti'i' ?), Sun Wt'^uui r, p. 
32. Is ho identical with Lucius Valentinus Otlio, who odiLod tho Vj^ius 
Palatinum dc Triamjulia of Rhiitious in 1596? 


astronomical books and instruments, though lie had to receive 
the money from his tutor and account to him for the way it 
was spent. He made use of the Ephemerides of Stadius ^ to 
find the places of the planets, haying first learned the names 
of the constellations by means of a small celestial globe not 
larger than his fist, which he hid from Vedel, and could 
only use when the latter was asleep. Though this state of 
things at first produced some coolness between tutor and 
pupil, it appears that they soon renewed their friendly 
intercourse. Tycho could not but see that Vedel was only 
doing his duty, and Vedel gradually had to acknowledge 
that the love of astronomy had become so deeply rooted in 
his pupil that it was utterly impossible to force him against 
his will to devote himself to a study he disliked, or at least 
looked on with indifference. Another circumstance which 
was a bond of union between them was that the learned 
men whose society Vedel sought were to a great extent the 
same to whom Tycho looked for instruction. Thus the 
above-mentioned Valentine Thau had a great regard for 
Vedel, and even tried to get him to enter the service of the 
Elector, while Homilius was a son-in-law of Oamerarius, the 
most renowned of the professors at Leipzig, and a man 
whom Vedel later in one of his writings mentions as his 
beloved teacher.^ Drawn together through their intercourse 
with these and other men of learning, Vedel and Tycho laid 
the foundation of a warm friendship which lasted through 

' Published at Cologne in 1556 for the years 1554-70, again in 1559 and 
1560, being continued to the year 1576. Tounded on the Prutenio tables. 

^ Joachim Liebhard (who changed his name to Camerarius because there 
had been several Kdmmerer in his family), born at Bamberg in 1500, died at 
Leipzig in 1574; published the Commentary of Theon as an appendix to the 
edition of Ptolemy edited by Gryneeus in 1538; wrote a book on Greek and 
Latin arithmetic (see Kastner, Gesch. d. MatJiem., i. p. 134), and published in 
1559 a book, De eorum qvi Cometce appellantur, Nominibus, Natara, Caussis, 
Sir/niJlcationCf in which he shows from history that comets sometimes announce 
evil, sometimes good events. 



Though Tycho was during the greater part of the time 
he spent at Leipzig obliged to study astronomy in secret, he 
did not long content himself with the use of the Epheme- 
rides of Stadius, but procured the Alphonsine tables and 
the Prutenic tables.-' "We have already mentioned that the 
former were founded on the Ptolemean planetary system and 
the observations of the Arabs, as well as those made under 
the direction of Alphonso X. of Castile in. the thirteenth 
century ; while the latter, which got their name from being 
dedicated to Duke Albrecht of Prussia, were the work of 
Erasmus Eeinhold, a disciple and follower of Copernicus. 
Tycho soon mastered the use of these tables, and perceived 
that the computed places of the planets differed from their 
actual places in the sky (even though he only inferred the 
latter from the relative positions of the planets and adjacent 
stars), the errors of the old Alphonsiue tables beiug much 
more considerable than those of their new rivals. He even 
found out that Stadius had not computed his places correctly 
from Reinhold's tables. And already at that time, while 
Tycho was a youth only sixteen years of age, his eyes were 
opened to the great fact, which seems to us so simple to 
grasp, but which had escaped the attention of all European 
astronomers before him, that only through a steadily pursued 
course of observations would it be possible to obtaiu a better 
insight into the motions of the planets, and decide which 
system of the world was the true one. An astronomical 
phenomenon which took place in August 1563, a conjunc- 
tion of Saturn and Jupiter, which in those days was looked 
on as a very important one, owing to the astrological signifi- 
cance it was supposed to have, induced him to begin at once 
to record his observations, even though they were taken 
with the crudest implements only. A pair of ordinary 

^ In his observations from 1563-64 he also mentions the Ephemerides of 
Carellus (Venice, 1557). 


compasses was all lie had to begin with ; by holding the 
centre close to the eye, and pointing the legs to two stars 
or a planet and a star, he was able to find their angular 
distance by afterwards applying the compasses to a circle 
drawn on paper and divided into degrees and half degrees. 
His first recorded observation was made on the 1 7th August 
1563/ 3'iid on the 24th of August in the morning he noted 
that Saturn and Jupiter were so close together that the 
interval between them was scarcely visible.^ ^The Alphon- 
sine tables turned out to be a whole month in error, while 
the , Prutenic ones were only a few days wrong as to the 
moment of nearest approach. Tycho continued his obser- 
vations, partly with the above-mentioned tool, partly using 
eye-estimations as to which stars formed with a planet a 
rectangular triangle, or which stars were in a right line 
with it. But in the following year he provided himself 
with a "radius," or "cross-staff," as it used to be called 
in English, one of the few instruments employed by the 
intrepid navigators who discovered the new worlds beyond 
the ocean.* It consisted of a light graduated rod about three 
feet long and another rod of about half that length, also 
graduated, which at the centre could slide along the longer 

1 Die 17, H. 13, M. 15, Erat <5 in 7 Gr. 8 lat. Mer. 3 Gr. ad fixas. 

" " Intervallum Tj et li matutino tempore vix observatione oeulari notari 
potuit : in hac nocte enim uteique se invicem obumbrabat suis radiis sed 
latitude ipsorum diversa adhuc erat, h enim meridionalior ipso 11 erat. Die 
27 (astron. 26) Mane vidi 11 cum h obtinere eandem alt. ab borizonte, hinc 
licet conjicere eorum 6 jam prseteriisse sed propius erant ab invicem dispositi 
quam ante triduum : quare etiam tempus aui^uylas propinquius huic 27 Aug. 
quam priori 24 fuisse manifestum est. In utroque autem die paulo ante 
ortum © distantiam ipsorum observavi." — MS. volume of observations, 1563- 
1581 incl., in the Royal Library at Copenhajjen {Gamle Eongdige Samlinger, 
4to, No. 1S24). The early observations (up to 1577) only exist in this copy, 
the originals would seem to be lost, at least they are not at Copenhagen. 

^ In French called arbalite or arialestriUe, in Spanish iallestUla, in German 
Jacohsstah. It seems to have been invented by Regiomontanus, and is de- 
scribed in his Problemata XVI. de Cometm Longitudine, written in 1472, and 
printed in 1 531 in Schoner's Descriptio Cometm. 


one, so that they always formed a right angle. The 
instrument could be used in two ways. Two sights might 
be fixed at the ends of the shorter rod, and one at the 
end of the longer rod, and the observer, having placed 
the latter close before his eye, moved the cross-rod along 
until he saw through its two sights the two objects of 
which he wanted to measure the angular distance. Or 
one of the sights of the shorter arm might be movable, and 
the observer first arbitrarily placed the shorter arm at any 
of the graduations on the longer one, and then shifted the 
movable sight along until he saw the two objects through 
it, and a sight fixed at the centre of the transversal arm. 
In either case the graduations and a table of tangents 
furnished the required angle. Tycho's instrument was of 
the latter kind, and was made accordiag to the directions of 
Gemma Frisius. He got his friend Bartholomeeus Scultetus 
to subdivide it by means of transversals, which method of 
subdividing small intervals was then beginning to be used, 
and which Tycho ascribes to Homilius. The earliest obser- 
vations stated to have been made with the radius are from 
the I st of May i 5 64, and Tycho says that he had to use it 
while his tutor was asleep, from which we see that Vedel 
had even at that time not given up his resistance to his 
pupil's scientific labours. The observer soon found that the 
divisions did not give the angles correctly, and as he could 
not get money from Vedel for a new instrument, he con- 
structed a table of corrections to be applied to the results of 
his observations.'' This is deserving of notice as the first 
indication of that eminently practical talent which was in 
the course of years to guide the art of observing into the 
paths in which modern observers have followed. Kepler, 
who more than any one else was able to appreciate his great 

.' Astronomice Instauratce Mcchanica, fol. G. 2. For a speoiinen of the 
observations see Appendix A. at end of this volume. 


predecessor, justly says that the " restoration of astronomy " 
was " by that Phoenix of astronomers, Tycho, first con- 
ceiyed and determined on in the year i 564." ■*■ 

While occupied with the study of astronomy and occa- 
sional observations, Tycho, like everybody else at that time, 
believed in judicial astrology, and now and then worked 
out horoscopes for his friends. He even kept a book in 
which he entered these " themata genethliaca." He men- 
tions in a letter/ written in 1588 to the mathematician 
Caspar Peucer, the son-in-law of Melanchthon, that he 
had during his stay at Leipzig made out the nativity of 
Peucer, and found that he was to meet with great 
misfortunes, either exile or imprisonment, and that he 
should become free when about sixty years of age, through 
the agency of some "martial" person. This prediction 
chanced to turn out correct, as Peucer ia i 574 was deprived 
of his professorship at Wittenberg, and kept in a rigorous 
imprisonment till 1586, being suspected of a leaning to 
Calvinism. From a lunar eclipse which took place while 
he was at Leipzig, Tycho foretold wet weather, which also 
turned out to be correct.^ 

Tycho left Leipzig on the 1 7th May 1565 with Vedel 

^ Tahulce Svdolphince, title-page. 

" Printed in Besenii Inseriptiones Hafnimses (Hatnise, 1668), pp. 392 et 
seq. ; and in Weistritz, Lebensbe&chreibung des T. v. Brake, i. pp. 239 et seq. 
(the matter referred to ocoura on p. 259). 

' In the volume of observations, 1563-81, there follow, after April 19, 1565, 
sixteen pages headed "Notationes interiectse," of various contents. On a 
vacant quarter page is written in a different hand: "Duobus sequentibus 
annis nullaa extant observationes Brahei, sed earum loco sequebantur anno- 
tationes qualescunque in codice." Also in another hand is the following: 
"Tycho Brahe Tomo II. Epistolarum aliqvando excuso sed non edito fol. 
54 scribit se hujus eclipsis tempore adhuo Lipsise studiorum causa com- 
moratum, et pluvium tempus cum meteovis humidis ex hac eclipsi prae- 
dixisse." Among the notes is also "Observatio XII. dierum et noctium 
statim sequentium natalem Christi in Anno 1564 complete, pro coustitutione 
et temperamento 12 mensium Anni 1565 proximo seqventis." The probable 
weather for January is 0(mcluded from the weather on December 26th ; that 
for ^February from the 27th, and so on. 


to return to Denmark. During Ms absence from tome war 
tad broken out between Denmark and Sweden, and Ms 
uncle, Jorgen Brabe, who held the post of vice-admiral, 
probably considered that his nephew's proper place at such 
a time was in his native country. Travelling by way of 
Wittenberg, they reached Rostock on the 25th May, and 
succeeded in crossing to Copenhagen without meeting any 
hostile cruisers. Whether the uncle had become reconciled 
to the substitution of the study of astronomy for that of 
law, is not known with certainty ; but the two relatives did 
not long enjoy each other's company, as Jorgen Brahe, who 
had just returned from a naval engagement in the Baltic 
(near the coast of Mecklenburg), died on the 21st June 
I 565. It happened that King Frederick II., when riding 
over the bridge which joined the castle of Copenhagen and 
the town, fell into the water. Jorgen Brahe was in his 
suite, and hastened to help the king out; but a severe 
cold he caught in consequence developed into an illness 
which proved fatal ia a few days. After his uncle's death 
there was nothing to keep Tycho at home. Another uncle, 
Steen BUle, maintained that he should be left to follow his 
own inclinations ; but, with this exception, all his relations 
and other nobles looked with coldness at this young man 
with his odd taste for star-gaziag and his dislike to what 
they considered sensible occupations. He was, therefore, 
glad to escape from these surroundings to others more 
congenial, and early in 1566 he left Denmark for the 
second time, and arrived at Wittenberg on the i 5th April. 
The University of Wittenberg had been founded ia 1502, 
and had then for nearly fifty years been one of the most 
renowned in Europe, possessing great attractions for Pro- 
testant students. Here Luther had lived, and from this 
hitherto insignificant spot had shaken the spiritual despotism 
under which the world had suffered so long ; and a few years 


tad only elapsed since tlie death, of Melanchtton had 
deprived the University of an accomplished scholar as well 
as a faithful and indefatigable worker for the Reformed 
faith. There were still many men of celebrity following 
in their footsteps, and keeping up the high reputation they 
had made for the University. Mathematics were specially 
cultivated at Wittenberg, because, as the Statutes stated, 
without them Aristotle, " that nucleus and foundation of all 
science," could not be properly understood. At the instance 
of Melanchthon, two chairs of Mathematics were founded, 
" Mathematum superiorum " and " inferiorum," the holder 
of the former having to lecture on astronomy — that of 
the latter on algebra and geometry. To Danish students 
Wittenberg had since the Eeformation been a favourite 
resort, and, among a number of young countrymen, Tycho 
Brake also found his former tutor, Vedel, who had arrived a 
few months before. We do not possess any information as 
to how Tycho spent his time at Wittenberg ; all we know 
is that he had the advantage of studying under the above- 
mentioned Caspar Peucer, Professor of Medicine and Phy- 
sician in ordinary to the Elector of Saxony. This man, 
who was distinguished both as a mathematician, a physician, 
and a historian, had been invested with unusual authority 
over the University.''- In the history of astronomy Peucer 
is known as the author of a few treatises, among which 
is one on spherical astronomy. Tycho, however, did not 
profit very much from Peucer 's instruction, as the plague 
broke out at Wittenberg, so that he was induced to leave 
it on the 1 6th September, after a stay of only five months,^ 

^ As Prfficeptor primarius totius Academic. We have already mentioned 
Peuoer's subsequent misfortune. He died in 1602. 

^ Tyoho probably remembered that the well-known astronomer Erasmus 
Reinhold, author of the Prutenio tables and professor .it Wittenberg, had 
in 1553 vainly tried to escape the plague by fiying from Wittenberg to 
Saalfeld, where he died. 


and to go to Eostock, where he arrived on the 24th 
September, and was matriculated at the University a few 
weeks later.-*^ 

Though not as celebrated as the University of Wittenberg, 
Eostock was also much frequented by Scandiaavian students, 
a natural consequence of its being situated close to the shore 
of the Baltic, and within easy reach from the Northern 
countries. It can hardly have been the wish of studying 
astronomy under any of the professors at Eostock which 
induced Tycho to take up his abode there, for there was 
not at that time any savant attached to the University of 
Eostock who occupied himself specially with astronomy ; 
and only one, David Chytraeus, otherwise well known as a 
theological author, is very slightly known in the history of 
astronomy as one of the numerous writers on the new star 
of 1572. But if there were no astronomers at Eostock 
(and, indeed, they were not numerous anywhere), there 
were several men who devoted themselves to astrology and 
alchemy, in addition to mathematics or mediciae. It must 
be remembered that it was at that time easy enough to 
be thoroughly acquainted with the little that was known 
in several sciences, and men frequently exchanged a pro- 
fessorship of medicine for one of astronomy or divinity. 
The connection of medicine in particular with astronomy 
was supposed to be a very intimate one, and as physicians, 
if they kept to what we should call their proper sphere, 
could do little but grope in the dark, they were only too 
glad to call in the aid of astrology to make up for the 
deficiency of their medical knowledge. . The idea of a 
sonnection between the celestial bodies and the vital action 
Df the human frame was a natural consequence of the 

1 As " Tycho Brahe, natus ex nobili familia in ea parte regni Danici quae 
Jioitur Scania." See G. 0. F. Lisch, Tycho Brahe und seine Verhdltnisse zu 
Weeklenhurg, in Jahrhiicher des Vereins fur MecHenburgiscke GescMchte, 
sxxiv., 1869 (Reprint, p. 2). 


Aristotelean and scholastic views of the kosmos and of tte 
dependence of the four elements of the sublunary region 
on the movements in the sethereal part of the universe. 
The dependence of vegetable life on the motion of the 
sun in the ecliptic, and the similarity of the period of the 
moon's orbital motion to that of certain phenomena of 
human life, were looked upon as proofs of the connection 
between the sublunary and the sethereal worlds ; and as the 
human body was composed of the elements, it would, like 
these, be influenced by the forces, chiefly the planets, by 
which the celestial part of the kosmos exercised its power. 
Thus it was supposed that the state of the body was de- 
pendent on the positions of the planets among the signs of 
the zodiac, and that the power of the Deity over the fate of 
man was also exercised by the medium of the stars.-"- Galileo 
had not yet overthrown the Aristotelean system of aSTatural 
Philosophy, and Bacon had not yet taught us to look for 
the explanation of the phenomena of nature by seeking for 
the mechanically acting causes through observation and in- 
duction, instead of through metaphysical speculation. Until 
this was done, it is not to be wondered at that the greatest 
minds believed in astrology ; and it only shows the narrow- 
mindedness of some modern writers, and their ignorance 
of the historical development of man's conception of nature, 
when they, on every occasion, sneer at the greatest men of 
former ages for their belief in astrology. 

Among the professors at Rostock was Levinus Battus, 
Professor of Medicine, born in the Netherlands, and origi- 
nally a mathematician. He has left writings on alchemy, 
and was a follower of Paracelsus ; so that it is likely enough 
that Tycho, who afterwards paid a good deal of attention 
to chemistry, attended his lectures. Tycho does not seem 
to have taken observations regularly at that time ; at 

■• " Astra regunt hominem, sed regit astra Deus." 


least we do not possess any made at Eostock earlier than 
January 1568. But shortly after Ms arrival, on the 
28th October 1566, a lunar eclipse took place, and Tycho 
posted up in the college some Latin verses, in which he 
announced that the eclipse foretold the death of the Tur- 
kish Sultan. It was natural to think of him, as Solimaa, 
who was about eighty years of age, had the year before 
startled Christendom by his formidable attack on Malta, 
which -was heroically and successfully defended by the 
Knights of St. John. A few weeks later news was received 
of the Sultan's death ; but unluckily he had died before the 
eclipse, so that the praise Tycho received for the prophecy 
was not unmingled with sneers, while he defended himself 
by explaining the horoscope of Soliman, from which he had 
drawn his conclusions as to the Sultan's death.^ 

An event took place at Eostock soon afber this, which 
was a good deal more unfortimate for Brahe, and which has 
become more widely known than many other and much 
more important incidents in his life. On the i oth Decem- 
ber 1566 there was a dance at Professor Bachmeister's house 
to celebrate a betrothal, and among the guests were Brahe 
and another Danish nobleman, Manderup Parsbjerg. These 
two got into a quarrel, which was renewed at a Christmas 
party on the 27th, and finally they met (whether acciden- 
tally or not is not stated) on the 29th, at seven o'clock in 
the evening, " ia perfect darkness," and settled the dispute 
with their swords. The result was that Tycho lost part 
of his nose, and in order to conceal the disfigurement, he 

^ In a marginal note in the volume of observations, 1563-81 (printed in 
DaTishe Magazin, ii. p. 177), Tycho states that Soliman died a few days 
before the eclipse. In reality he died on 6th September, while besieging the 
Hungarian fortress Szigeth, though his death was kept secret for more than a 
fortnight. There is a written pamphlet by Tycho, apparently intended to be 
printed, in the Hofbibliothek at Vienna, He Eclipsi Imnari, 1573, Mense 
Decembri, in which the eclipse of 1566 and the prediction of the Sultan's 
death are also,treated of. Triis, in Danslee Samlirujer, 1869, iv. p. 255. 


replaced tHe lost piece by another made of a composition 
of gold and silver. Gassendi, wlio recounts all these 
details, adds that Willem Jansson Blaev, who spent two 
years with Tycho at Hveen, had told him that Tycho 
always carried in his pocket a small bos with some kind 
of ointment or glutinous composition, which he frequently 
rubbed on his nose.''- The various portraits which we pos- 
sess of Tycho show distinctly that there was something 
strange about the appearance of his nose, but one cannot 
see with certainty whether it was the tip or the bridge that 
was injured, though it seems to be the latter. A very 
venomous enemy of his, Eeymers Bar, of whom we shall 
hear more farther on, says that it was the upper part of 
the nose which Tycho had lost.^ 

As already remarked above, Tycho does not seem to have 
taken many observations about this time, but on the 9th 
April 1567 an eclipse of the sun took place which he 
observed. At Eostock the eclipse was of about seven digits, 
but at Eome it was total, and the solar corona was seen by 
Clavius. In the summer of 1567 Tycho paid a visit to 
his native country, but he does not appear to have been 
altogether pleased with his reception there, and at the end 
of the year he returned to Eostock, where he arrived on the 
1st January I 568. Already, at six o'clock on the following 
morning, he commenced to take observations, though he had 
not an instrument at hand, and therefore had to content 
himself with noting down the positions of Jupiter and 
Saturn among the stars. On the 14th he wrote a letter to 

^ Gassendi (p. 10) adds, that according to the Epistles of Job. Bapt. Laurua 
(Protonotarius Apostolicus of Pope Urban VIII.), the dispute between Brahe 
and Parsbjerg was as to which of them was the best mathematician. But 
this is probably only gossip. They are said to have been very good friends 
afterwards. Towards the end of this book we shall see that Parsbjerg com- 
plained of the fight being referred to in Tycho's funeral oration. 

" Delambre, Aati; Moderne, i. p. 297 ; Kastner, Geschiohte der Mathematik, 
iii. p. 475. 


a countryman Johannes Aalborg (whose acquaintance he had 
probably made at Eostock the previous winter), that he had 
since his arrival been staying at the house of Professor 
Levinus Battus, but that he hoped the same day to take 
up his residence in the College of the Jurists, where he 
would have a convenient place for observing. (We find 
that he commenced to use the radius or cross-staff there 
on the I pth.) In this letter, which is printed by Gassendi,^ 
Tycho says that he intends remaining over the wiuter in his 
new abode, and adds : " But you, my dear Johannes, must 
keep perfect silence with regard to those reasons for my 
departure which I have confided to you, lest anybody should 
suspect that I complain of anything, or that there was some- 
thing in my native land which obliged me to leave it. For 
I am very anxious that nobody should think that I am com- 
plaining of anything, as in truth I have not much to com- 
plain of. I was indeed received better in my native land by 
my relations and friends than I deserved ; only one thing 
was wanting, that my studies should please everybody, and 
even that may be excused. There are many denunciators 

But though Tycho was dissatisfied with the want of 
sympathy which his countrymen showed for his love of the 
stars, it appears that there must have been those in Den- 
mark who appreciated the steady perseverance with which 
the young nobleman devoted himself to study, and the first 
sign of this appeared soon after. On the .14th May I 568, 
King Frederick II. granted him under his hand a formal 
promise of the first canonry which might become vacant in 
the Chapter of the Cathedral of Koskilde in Seeland.^ To 
imderstand this, we must mention that the Danish cathedral 

^ Page II, and reprinted in Tychonis Brahei et ad eum doctor um Virorum 
EpistolcE, Havnise, 1876-86, p. I. 

^ The letter may be seen in Danske Magazin, ii. p. iSo (Weistritz, ii. 
P- 45)- 


chapters were not abolished at the Reformation (1536), 
but that their incomes for more than a century were spent 
to support men of merit (or who were supposed to be such), 
and especially men of learning. The members were still 
called canons, and if they lived about the cathedral, they 
formed a corporate body and managed the temporalities of 
the cathedral and its associated foundations. Gradually 
the canonries became perfect sinecures, and the kings 
assumed the right to iill them, until their property, in 
the course of the second half of the seventeenth century, 
was taken possession of by the Crown. One of these 
sinecures was thus by royal letter promised to Tycho Brahe, 
who now might feel certain that means of following his 
favourite pursuit would not be wanting. He was possibly 
still at Eostock when this letter was issued, and it is not 
known when he left this town (his last recorded observation 
there is of the 9th February), but it must have been early 
in the year, as he was at Wittenberg some time in i 568,-' 
and went to Basle in the course of the same year, where he 
was matriculated at the University.^ He must have stayed 
at Basle till the beginning of the following year, when we 
find him at Augsburg, where he began to observe on the 
14th April. On the way he had paid a visit to Cyprianus 
Leovitius (Livowski), a well-known astronomer, who lived 
at Lauingen, in Suabia/ who had published an edition 
of the trigonometrical tables of Eegiomontanus (TabulcB 
Diredionum, 1552), various Ephemerides, and an astro- 
logical book on the signification of conjunctions of planets, 
eclipses, &c.* Leovitius thought the world was likely to 

■" Mechanica, fol. G. 2. 

^ R. Wolf, Geschiehte der Astronomie, p. 271. 

' Born in 1524 in Bohemia, died at Lauingen in 1574. 

* The original edition (of 1564) is in German (see Pulkova Library Cat., 
p. 382), and not in Latin, as stated by Lalande. The London edition of 1573 
(of which more below) is in Latin, and has the title given by Lalande. 


:ome to an end in 1584, after the next great conjunction, 
md he was, on the whole, more of an astrologer than of 
m astronomer. Tycho asked him, among other things, 
ivhether he ever took ohservations, as he might thereby 
see that the Ephemerides, which he had with some trouble 
computed from the Alphonsine tables, did not agree with 
;he heavens. To this Leovitius answered that he had no 
nstruments, but that he sometimes "by means of clocks" 
)bserved solar and lunar eclipses, and found that the former 
igreed better with the Copernican (Prutenic) tables, the 
atter better with the Alphonsine, while the motion of the 
hree outer planets agreed best with the Copernican, the 
nuer ones with the Alphonsine tables.-*- It does not seem 
;o have struck him, nor, iadeed, any one before Tycho, that 
he only way to produce correct tables of the motions of the 
)lanets was by a prolonged series of observations, and not by 
aking an odd observation now and then. 

In the ancient free city of Augsburg Tycho seems to 
lave felt perfectly at home. Dear to aU Protestants as 
)eiag the place where the fearless Reformers had declared 
heir faith, and where the Protestant princes and cities of 
Germany had signed the " Confession of Augsburg," the 
ity possessed the further attraction of having many hand- 
ome public and private buUdings and spacious thorough- 
ares, while the society of many men of cultured tastes and 
irincely wealth (such as the celebrated Fugger family), 
lade it an agreeable place of residence. Among the men 
rith whom Tycho associated here were two brothers, Johann 
Japtist and Paul Hainzel, the former burgomaster, the 
itter an alderman (septem-vir). Both were fond of astro- 
omy, but Paul particularly so, and they were anxious to 
rocure some good instrument with which to make observa- 
Lons at their country-seat at Goggingen, a village about an 

' Astr. Inst. Progymnasmata, p. 70S. 


Engiisli mile south of Augsburg.-^ Tycho tells us in his 
principal work, Astronomice Instauratce Frogymnasmata, at 
some length, that he was in. the act of making out how large 
an instrument would, have to be in order to have the single 
minutes marked on the graduated arc, when Paul Hainzel 
came in and a discussion arose between them on the subject. 
Tycho was convinced that no good would result to science 
from using ' ' those puerile tools " with which astronomers 
then observed, and he concluded that it was necessary to 
construct a very large quadrant, so large that every minute 
could readily be distinguished, and fractions of a miante 
estimated ; " for he did not then know the method of sub- 
dividing by transversals." This last remark is curious, as 
we have already seen that he attributed his acquaintance 
with the method to Scultetus, but he evidently means that 
it had not yet occurred to him to use this plan on an arc 
as well as on a rectilinear scale. He spoke in favour of con- 
structing a quadrant, as he had already made several of 
three or four cubits radius (this is the only evidence we 
have of this fact), and was sufficiently familiar with the 
cross-staff to know that no accurate results were to be 
expected from it. The outcome of this discussion was that 
Paul Hainzel undertook to defray the expense of a quadrant 
with a radius of 14 cubits (or about 19 feet). The most 
skilful workmen were engaged, and within one month the 
huge instrument was completed. Twenty men were scarcely 
able to erect it on a hUl in Hainzel's garden at Goggingen ; 
it was made of well-seasoned oak ; the two radii and the arc 
were joined together by a framework of wood, and a slip of 
brass along the arc had the divisions marked on it. Unlike 
all Tycho's later quadrants, it was suspended by the centre, 

1 The latitude of Goggingen is 48° 20' 28", and that of St. TJlrich's Church, 
Augsburg = 48° 21' 41" (Bode's Jahrhuch, Dritter Supplementband, pp. 166- 
167). Hainzel found, in 1572-73, the latitude of Goggingen=48° 22' with 
the great quadrant {Progymnasmata, p. 361). 


and was movable round it, the two siglits being fixed on 
one of the radii, and the measured altitude being marked 
by a plumb-line. The weighty mass was attached to a 
massive beam, vertically placed in a cubical framework of 
oak, and capable of being turned round by four handles, so 
as to place the quadrant in any vertical plane. The frame- 
work or base was strongly attached to beams sunk in the 
ground. There was no permanent roof over it, but some 
kind of removable cover. The instrument stood there for 
five years, until it was destroyed in a great storm ia 
December 1574, and some observations made with it of 
the new star of 1572 and other fixed stars are pub- 
lished in Tycho's Progymnasmata} He does not himself 
appear to have observed with it, although we possess his 
observations made at Augsburg, with few interruptions, 
from April I S 69 to April i 5 70. Some of these are, as 
formerly, mere descriptions of the positions of the planets, 
stating with which stars they were in a straight line or ia 
the same vertical ; others are made with the cross-stafi"; others 
again with a " sextant" or instrument for measuring angles 
in any plane whatever, which he had designed about this 
time. This instrument, which he presented to Paul Hainzel, 
consisted of two arms joined by a hinge like a pair of com- 
passes, with an arc of 30° attached to the end of one arm, 
while the other arm could be slowly moved along the arc 
by means of a screw.^ We shall farther on describe this 
instrument in detail. 

In addition to these instruments, Tycho while at Augsburg 
arranged for the construction of a large celestial globe five 
feet in diameter, made of wooden plates with strong rings 
inside to strengthen it. It was afterwards covered with 

' Pages 360-367. The quadrant is figured ibid., p. 356; also in Astroii. 
Inst. Mechanica, fol. E. 5, and in Barretti Historia Ccelcstis, p. cvii. Abuut 
its destruction, see T. B. et ad mm Doct. Vir. Epistolce, p. 17. 

^ Figured in Mechanica, tot. E. 2. 


tkin gilt brass plates, on wiicli the stars and the equator 
and colures were marked. It was not finished when Tycho 
left Augsburg ; but Paul Hainzel, who was under great 
obligations to him for having designed the quadrant and 
given him the newly-constructed sextant, readily undertook 
to superintend the completion of it. 

At Augsburg Tycho made the acquaintance of Pierre de 
la Ramfe, or Petrus Eamus, Professor of Philosophy and 
Rhetoric at the College PLoyal at Paris, who had been 
obliged to leave Prance several times owing to his adherence 
to the Huguenot party, and the odium he had drawn on 
himself by his opposition to the then all-powerful Aristotelean 
philosophy. He wanted to discourage the exclusive study 
of this time-honoured system of philosophy, now worn to 
a shadow, which had become a mere cloak for stagnation, 
bigotry, and ignorance, and to introduce in its place the 
study of mathematics in the University of Paris. But his 
zeal only procured him much enmity and persecution ; he 
had to apologise for his abuse of the Peripatetic philosophy 
before the Parliament of Paris, and by sentence of special 
royal commissioners appointed to investigate the matter, 
Aristotle was reinstated as the infallible guide to learning. 
Eamus had therefore for a while withdrawn from France, 
but, unluckily for himself, he returned in I S 7 1 , and perished 
the following year in the massacre of St. Bartholomew. 
This man, who was naturally inclined to hail with pleasure 
a rising star in a science closely allied to his own, happened 
to be at Augsburg in 1570, and became acquainted with 
Tycho Brahe through Hieronymus Wolf, a man of great 
learning, especially in the classical languages, and himself 
drawn to Tycho by his love of astrology. Having been 
invited by Hainzel to inspect the great quadrant, Eamus 
expressed his admiration of this important undertaking, so 
successfully carried out by a young man only twenty-three 



years of age, and begged Ilim to publisL a description of 
it. In liis work Scholarum Mathematicarum Libri XXXI., 
published at Basle in 1569 (only a few months before Hs 
conversation witli Tycho), Ramus liad advocated tlie building 
up of a new astronomy solely by logic and matbematics, and 
entirely without any hypothesis, and had referred to the 
ancient Chaldeans and Egyptians as having had a science 
of this kind, which had gradually by Eudosus and that 
terrible Aristotle been made absurd through the introduc- 
tion of solid spheres and endless systems of epicycles. 
Ramus explained his views to Tycho (who has left us 
an account of this conversation ■') ; but he answered that 
astronomy without an hypothesis was an impossibility, for 
though the science must depend on numerical data and 
measures, the apparent motions of the stars could only 
be represented by circles and other figures. But though 
Ramus could not bring over the young astronomer to his 
views, they could cordially agree in the desire of seeing 
the science of astronomy renovated by new and accurate 
observations, before a true explanation of the celestial 
motions was attempted ; and it can hardly be doubted that 
the conversation of this rational, clear thinker (so difEerent 
from a Leovitius, with his brain crammed full of astrology 
and other hazy and fanciful ideas) took root in the thought- 
ful mind of the young astronomer, and bore fruit in after 
years in that reformation of his science for which Ramus 
had hoped. 

Tycho Brahe left Augsburg in 1570, but the exact 
month is not known, nor the route by which he travelled. 
We only know that he passed through Ingolstadt, and 
called on Philip Apianus,^ a son of Peter Apianus (or Biene- 
witz), whose name is well known both by his having pointed 

^ In a letter to Rothmann, Efist. Astron., p. 60 ; see also Progymn., p. 359. 
^ Prot/ymn., p. 643. 


out that tlie tails of comets are turned away from tlie sun, and 
also by bis work Astronomicum CcBsarmm, to wMch we have 
already alluded. He was probably called back to Denmark 
by the illness of bis father, Otto Brabe, for the first sign of 
his having returned is an observation made on the 30th 
December 1570 at Helsingborg Castle, where his father 
was governor,-^ and it is known , that his brother, Steen 
Brabe, who was also abroad at that time, was called home 
by the alarming state of his father's health.^ Otto Brabe died 
at Helsingborg on the gth. May 1571, only fifty-three years 
of age, surrounded by bis wife and family. Tycho has in 
a letter to Vedel given a touching description of bis last 
moments.* His property of Knudstrup seems to have been 
inherited jointly by his eldest two sons, Tycho and Steen, 
the latter of whom was already the following year in a still 
existing document styled "of Knudstrup."* 

Tycho remained at home after bis father's death, paying 
occasional visits to Copenhagen, but spending most of bis 
time in Scania. He seems to have found it too lonely at 
Knudstrup, and soon took up his abode with bis mother's 
brother, Steen BiUe, at Heridsvad Abbey, about twenty 
English miles east of Helsingborg, and not very far from 
Knudstrup. Formerly there had been here a Benedictine 
monastery, which, like several others in Denmark, was not 
at once abolished- at the Reformation ; but in 1565 Steen 
Bille had been ordered to take possession of the Abbey, 
" because ungodly life was going on there," and to maintain 

' It can hardly be called an observation : " J Her. quasi post occasum © 
vidi quod (5 limbi illuminati extremitate distabat a % per duplicem diametrum 
Bui corporis, habebatque eandem prfficise cum % latitudinem visam." 

^ Danske Magazin, ii. p. 1S2 (Weistritz, ii. p. 50). 
' ^ T. B. et ad e«m Doct. Virorum Epistolm, pp. 1-3. In this letter Tycho, 
at Vedel's request, gives him a prescription against fever, and adds that he 
could give him others, but will wait till he sees him, as he does not like to 
put them in writing. 

* Danske Magazin, 4th Series, vol. ii. pp. 324-325. 


the Abbot, and to keep up divine service according to tlie 
Lutheran ritual, while he was to drive out " all superfluous 
learned and useless people." The Abbey does not appear 
to have been granted to him formally in fee till 1576.^ 
We have already mentioned Steen Bille as the only one of 
Tycho's relations who appreciated his scientific tastes, and 
he seems indeed to have been a man of considerable culture, 
who took an interest in more than one branch of learning 
or industry. Tycho says that he was the first to start a 
paper-mill and glass-works in Denmark. Whether it was 
from living with this uncle, or from some other cause, that 
Tycho for a while devoted himself more to chemistry than 
to astronomy, is uncertain, but from the 30th December 
1570 till November 1572 we do not possess a single astro- 
nomical observation made by him, while during this time he 
worked with great energy at chemical experiments, to which 
he had already paid some attention at Augsburg. His 
uncle gave him leave to arrange a laboratory in an outhouse' 
of the Abbey, and was evidently himself much interested in 
the work carried on there. ^ Whether the object of this 
work was to make gold, as was most frequently the case 
with chemical experiments made in those days, there is no 
evidence to show ; but even if this was not the case, there 
is nothing surprising in seeing an astronomer in the six- 
teenth century turn aside from the contemplation of the 
stars to investigate the properties of the metals and their 
combinations. We have already alluded to the idea of the 
universe as a whole, of which the single parts were in 
mystical mutual dependence on each other — an idea which 
had arisen among Oriental nations in the infancy of time, 
had thriven well owing to the mystical tendency of the 
Middle Ages, and had been gradually developed and formed 
into a complicated system by the speculations of philosophers 

^ Friis, Tyge Brahe, p. 31. ' Progymn., p. 298. 


of successive periods. The planets were the rulers of the 
elementary world and of the microcosmos, the moon being 
represented among the metals by silver, Mercury by quick- 
silver, Venus by silver, the sun by gold. Mars by iron, 
Jupiter by gold or tin, and Saturn by lead. It is therefore 
very probable that Tycho while working in the laboratory 
considered himself as merely for a while pursuing a special 
branch of the one great science, to the main branch of 
which he had hitherto felt specially attracted. But if these 
mystical speculations had as yet some power over his mind, 
they would seem gradually to have been pushed into the 
background, while cool and clear reasoning took their place, 
and guided him safely to his great goal — the reformation of 
practical astronomy. 

We have now followed Tycho through what may be con- 
sidered the first period of his life. By study and intercourse 
with learned men he had mastered the results of the science 
of antiquity and the Middle Ages. But though he had to 
some extent already, as a youth seventeen or eighteen years 
of age, perceived the necessity of a vast series of systematic 
observations on which to found a new science, he had hitherto 
shrunk from carrying out this serious undertaking himself, 
or had perhaps despaired of getting the means of doing so. 
But a most unusual and startling celestial phenomenon was 
now to occur, to rouse him to renewed exertion, and firmly 
fix in his mind the determination to carry out the plans he 
had so long entertained. 



On tlie evening of the i ith November 1572, Tycto Brate 
had spent some time in the laboratory, and was returning 
to the house for supper, when he happened to throw his 
eyes up to the sky, and was startled by perceiving an 
exceedingly bright star in the constellation of Cassiopea, 
near the zenith, and in a place which he was well aware 
had not before been occupied by any star. Doubtful 
whether he was to believe his own eyes, he turned round 
to some servants who accompanied him and asked whether 
they saw the star ; and though they answered in the 
affirmative, he called out to some peasants who happened 
to be driving by, and asked the same question from them. 
When they also answered that they saw a very bright star 
in the place he indicated, Tycho could no longer doubt his 
senses, so he at once prepared to determine the position of 
the new star. He had just finished the making of a new 
instrument, a sextant similar to the one he had made for 
Paul Hainzel, and he was therefore able to measure the 
distance of the new star from the principal stars in Cas- 
siopea with greater accuracy than the cross-staff would 
have enabled him to attain.-^ In order to lessen the 
weight, the instrument was not made of metal, but of 
well-seasoned walnut-wood, the arms being joined by a 
bronze hinge, and the metallic arc only 30° in extent, and 

■' The sextant is figured and described in Astr. Inst. Progymnasmata, 
p. 337 et seq. 


THE NEW STAR OF 1572. 39 

graduated to single minutes. The arms were four cubits, 
or about fiye and a half feet long/ three inches broad, and 
two inches thick ; and to steady the instrument an un- 
divided arc was attached to the arm which held the 
graduated arc, about eighteen inches from the centre, and 
passing loosely through a hole in the other arm, where it 
could be clamped by a small screw. This undivided arc 
and the long screw which served to separate the arms 
steadied the instrument, and kept its various parts in one 
plane. The graduated arc was not, as in his later instru- 
ments, subdivided by transversals, and the two sights were 
still of the usual kind, which he afterwards discarded, viz., 
two square metallic plates with a hole in the centre. The 
error of excentricity, caused by the unavoidable position of 
the observer's eye slightly behind the centre of the arc, 
was duly tabulated and taken into account. 

With this instrument Tycho measured the distance of 
the star from the nine principal stars of Cassiopea. We 
can easily picture to ourselves the impatience with which 
he must have awaited the next clear night, in order to see 
whether this most unusual phenomenon would still appear, 
or whether the star should have vanished again as suddenly 
as it had revealed itself. But there the star was, and con- 
tinued to be for about eighteen months, north of the three 
stars (now called (8, a, j Cassiopeaa) which form the pre- 
ceding part of the well-known W of this constellation, and 
forming a parallelogram with them. It was only a degree 
and a half distant from a star («) of the 4^ magnitude. 
Tycho continued, while the star was visible, to measure its 
distance from the other stars of Cassiopea ; and in order to 
find whether it had any parallax, he repeated these measures 
from time to time during the night, and even left the 

' One Tychonio cubit is =16.1 English inches (D'Arrest, Astr. Nadir., 
No. 1718, p. 219). 


sextant clamped in the interval between two observations, 
to make sure that no change had taken place in the instru- 
ment in the meantime. The star being circumpolar for 
his latitude, he was able to follow it right round the pole, 
and he took advantage of this circumstance to observe its 
altitude at the lower culmination by the sextant, as he did 
not at that time possess a quadrant. He placed it in the 
plane of the meridian with the one arm, which we may call 
the fixed one, and to which he had now attached an arc 
of 60°, resting horizontally on a window-sill and a short 
column inside the room.'' To ensure the horizontal posi- 
tion of the arm, it was moved until a plumb-line suspended 
from the end of the graduated arc touched a mark exactly 
at the middle of the arm,' and as the instrument might 
happen to be slightly moved while the observation was 
being made, a short graduated arc was traced at the middle 
of the arm, on which the plumb-line would immediately 
mark the small correction to be applied to the observed 
altitude. This simple but neat contrivance is highly, 
characteristic of Tycho ; we recognise here the modern 
principle of acknowledging an instrument to be faulty, 
and applying corrections for its imperfections to the results 
determined by it, a principle which we shall see he followed 
in the construction of all his instruments. From repeated 
observations he found the smallest altitude of the new star 
to be 27° 45', and consequently, as he assumed the latitude 
of Heridsvad to be 55° 5 8', the declination of the star was 
61° 47'. He remarks that the declination was as constant 
as the distances from the neighbouring stars, and that the 

^ The sextant in this position is figured in Progymnasmata, p. 348 ; 
Mechanica, fol. E. 3 verso. 

^ Tycho considers it necessary to quote Euclid iv. 15 and i. 12 in explana- 
tion of this {Progymn., p. 349). Euclid was apparently still considered an 
author with whose work but few were familiar (see H. Hankel, Zur GescJiichte 
der Mathematik im Alterthum und Mittclalter, p. 355). 

THE NEW STAR OF 1572. 41 

instrnment was not perfect enougli to stow tlie change o£ 
about a third of a minute wliicli the precession of the 
equinoxes made in the declination while the star was 
visible, an amount which even his later and more perfect 
instruments would hardly have been able to point out.^ 

With the sextant Tycho was not able to observe the 
upper culmination of the star, at which it was only 6° from 
the zenith. As a supplement to his own results, he there- 
fore gives in his later work ^ the observations made with 
the great quadrant at Augsburg by Paul Hainzel, which 
give a value of the declination agreeing within a fraction 
of a minute with his own. 

The observations with the sextant must have occupied 
Tycho during the winter of 157 2—7 3 , during which time 
the brightness of the new star had already commenced to 
decline considerably. When he first saw it, on the i ith 
November, it was as bright as Venus at its maximum 
brightness, and remained so during the month of Novem- 
ber, so that sharp-sighted people could even see it in the 
middle of the day, and it could be perceived at night 
through fairly dense clouds. In December it was some- 
what fainter, about equal to Jupiter; in January, a little 
brighter than stars of the first magnitude ; and in Feb- 
ruary and March, equal to them. In April and May it 
was like a star of the second magnitude ; in June, July, 
and August, equal to one of the third, so that it was very 

^ ProgyfMi., p. 351. Individual results of observations are not given, and, 
nnluclcily, the original observations of Nova are lost ; at least they are not in 
the volume of observations from 1563-81, repeatedly quoted. This only 
contains the following observations of Nova: — "1573 Die pentecostis 10 
Maji inter fiexuram Cassiopese et novam stellam 5S8', 580'. Inter supremam 
cathedrae et novam stellam 5E28', 5220'. Inter Schedir et novam stellam 
8S5', 7K52'. Confide his observationibus subtracta tamen instrument! parallaxi 
(5 gradus habent parallaxin 8 minutorura, 8 gradus habent 13). — August! die 
14 inter novam stellam et Polarem 25^9'." 

^ Proyymn., p. 360. 


like tlie principal stars in Cassiopea. It continued to 
decrease during September, so that it reached the fourth 
magnitude in October, and was exactly equal to k CassiopesB 
in November. At the end of the year and in January 
1574 it hardly exceeded the fifth magnitude; in February 
it came down to the sixth magnitude, and about the end of 
March it ceased to be visible. At the same time the colour 
gradually changed ; at first it was white, and by degrees 
became yellow, and, in the spring of 1573, reddish, like 
Betelgeuze or Aldebaran. About May 1573 it became like 
lead, or somewhat like Saturn, and seemed to remain so 
while the star was visible.-"- 

About the time when the new star appeared Tycho Brahe 
had prepared an astrological and meteorological diary for 
the following year, giving the time of rising and setting of 
the principal stars, the aspects of the planets, and the phases 
of the moon, together with their probable influence on the 
weather. To this diary he added an account of his obser- 
vations on the new star and its probable astrological signi- 
fication. Early in 1573 he went to Copenhagen on a -visit 
to his friend Professor Johannes Pratensis, and brought the 
manuscript with him. Pratensis had not yet heard of the 
new star, and would scarcely believe Tycho when he told 
him about it. Equally racredulous was another friend, 
Charles Dancey, French envoy at the Danish court, who 
invited Tycho and Pratensis to dinner as soon as he heard 
of the arrival of the former. During the dinner Tycho 
happened to mention the star, but Dancey thought he was 
joking and intendiug to sneer at the ignorance of Danish 
savants in astronomy, while Tycho only smiled, and hoped 
that the evening would be clear, so that they could see the 
star with their own eyes. The evening was favourable, and 

' Progymnasmata, pp. 300-302, and p. 591, the latter place being a reprint 
of the preliminary account printed in 1573- 

THE NEW STAK OF 1572. 43 

Pratensis and Dancey were as surprised as Tycho Had been 
when ttey saw tMs new star, so utterly different from a 
comet (the only class of celestial bodies with which anybody 
thought of comparing it), and yet, according to Tycho's 
observations, more distant than the planets, and probably 
belonging to " the eighth sphere," which had always hitherto 
been considered the very picture of immutability. Pratensis 
at once recollected the statement made by Pliny in the 
second book of his Natural History (on which he happened 
to be then lecturing at the University), that Hipparchus is 
said to have observed a new star ; and perceiving the im- 
portance of the manuscript essay which Tycho had given 
him to read, he urged him to have it printed. But Tycho 
declined, on the pretence that the essay had not received 
the final touches from his hand, but really because he was 
not quite free from the prejudice of some of his fellow- 
nobles, that it was not proper for a nobleman to write 

Tycho therefore returned to Scania with his manuscript. 
But when the spring came, and communication with Ger- 
many was reopened, he received from thence through Pra- 
tensis so many accounts of the star, both written and 
printed, containing a vast amount of nonsense, that he 
became inclined to let his own book be published, as it 
might serve to refute the erroneous statements circulated 
about the star. During a second visit to Copenhagen he 
was entreated to publish the book, not only by Pratensis, 
but also by his kinsman, Peter Oxe, high treasurer of Den- 
mark, whose sister had been the wife of Jorgen Brahe, and 
consequently had been a second mother to Tycho. Shaken 
in his resolution by the persuasions of this intelligent man, 
who even suggested that he might hide his name imder an 
anagram if he did not wish to put it on the title-page, 

^ Progymnasmata, p. 579. 


Tycho finally yielded so far as to allow Pratensis to let the 
account of the star and the plan of the meteorological diary 
be printed, omitting the details of the latter. The book 
was therefore printed at Copenhagen in the year 1573, but 
Tery few copies appear to have been distributed or sent 
abroad, so that it afterwards became necessary to reprint the 
more important parts of it in the greater work, Astronomioe 
Instauratce Prof/ymnasmata, on which Tycho was engaged 
during the last fourteen years of his life, and which was 
published after his death. The little book, De Nova Stella, 
is now extremely scarce, and does not appear to have been 
seen by any modern writer on the history of astronomy. It 
wUl therefore not appear inopportune if I give a somewhat 
detailed account of its contents in this place. ^ 

On the back of the title-page is a versified address to the 
author from Professor Joh. Francisci Eipensis, one of his 
earliest friends. Then follows a letter from Pratensis, 
dated 3rd May i 573,^ begging Tycho to print the book, 
at least the part relating to the star, the plan of the diary 
(if he should think the diary itself too long), and the fore- 
cast of the lunar eclipse. Tycho's answer comes nest, 
dated " Knusdorp," 5 th May. In this he remarks that 

^ The title given in Lalande's Sibliographie is erroneous. Tiie complete 
title is : " Tychonis Brahe, Dani, De Nova et NuUius Aevi Memoria Prius 
Visa Stella iam pridem Anno a nato Christo 1572 mense Nouembrj primum 
Conspecta, Oontemplatio Mathematica. Cui, yrsstei exactam Eclipsis Lunaris, 
hujas Anni, pragmatian, Et elegantem in Vraniam Elegiam, Epistola quoque 
Dedicatoria accessit : in qua, nova et erudita conscribendi Diaria Metheoro- 
logica Methodus, utriusque Astrologise Studiosis, eodem Autore, proponitur. 
Cuiu:^, ad hunc labentem annum, Exemplar, singular! industria elaboratura 
conscripsit, quod tamen, niultiplicium Schematum exprimendorum, quo totum 
ferme constat, difEcultate, edi, hac vice, temporis angustia non patiebatur." 
Hafnise Impressit Lavrentius Benedict], 1573. Printed in small 4to, 106 pp. 

^ Evidently written expressly for the book, as there is a previous letter 
from Pratensis in existence dated i6th April {1\ B. et ad earn Doct. Vir. 
Epist., p. 8), in which he says that the figures are being cut, but that there 
is some difficulty about the paper ; also that the word, lucubrationes is not 
a good one for the title. Tycho must therefore have consented to the 
publication long before the 3rd of May. 

THE NEW STAE OF 1572. 45 

the intricate diagrams and figures of the diaiy would be 
very troublesome to reproduce, and the year is nearly half 
over, so that it would not be worth while printing the- 
diary. As to the star, he fears that the account of it is a 
very immature one ; still he will let it be published, partly 
because his friend wishes it, partly because some of the 
German accounts of the star place it at a distance of only 
twelve or fifteen semi-diameters of the earth, while his own 
observations of its distance from Schedir (a CassiopeEe) 
show that it is situated in ipso ccelo. He has made his 
observations with a new and exquisite instrument, much 
better than a radius or any similar instrument, and the 
horizontal parallax of three or four degrees, which the star 
would have if it were as close to us as stated by the 
German writers, would have been easily detected. "0 
ocecos ci^li spectatores ! " Somebody had thought that it 
was a comet with the tail turned away from the earth, but 
that writer has forgotten what Apianus and Gemma Frisius 
have taught us, that the tails of comets are turned away 
from the sun, and not from the earth. Others thought the 
star was one of the tailless comets which the ancients 
called Crinitce ; others again that it belonged to the class 
called Mosce, with a disc gradually fainter towards the edges. 
But it looks exactly like other stars, and nothing like it 
has been seen since the time of Hipparchus. It does not 
seem likely that it will last beyond September, or at most 
October (1573), and it would be far more marvellous if 
it remained, for things which appear in the world after 
the creation of the universe ought certainly to cease again 
before the end of the world. As his own conclusions thus 
differ so much from those of the German writers, he con- 
sents to let his book be printed, and sends it herewith,^ 

^ As mentioned above, the book was actually in the printer's hands when 
this was written. 


leaving him to settle the title, and only begging him to 
suppress the author's name or to hide it in an anagram, as 
many people are perverse enough to think it an ingetis 
indecus for a nobleman to work in the free and sublime 
sciences. He has not had time to revise the manuscript 
owing to domestic affairs,'^ other studies, and social intercourse 
with friends. He next proceeds in some poetical lines ^ to 
declare his intention of seeing more of the world in order 
to increase his knowledge, as it will be time enough later 
on to return to the frigid North, and, like other nobles, 
waste his time on horses, dogs, and luxury, unless God 
should reserve him for something better. Having (in 
prose) assured Pratensis of his lasting friendship wherever 
they both may be, and reminded him that they shall at all 
events be contemplating the same sun, moon, and stars, he 
gives vent to his feelings in the following lines, which may 
serve as a specimen of Tycho's poetical effasions : — 

" Et quia disiunctis, Eadios coniungere in unum 

Non licet, et nosmet posse videre simul, 
Jungemus radios radiis radiantia Olympi, 

Quando micant claro, sydera clara. Polo. 
Tunc ego, quam specto, figens mea lumina ccelo 

Est quoque luminibus, Stella videnda, tuis. 
Sic oculos pariter Coelum coniunget in ununi, 

Nostra licet iungi corpora Terra vetet." 

Finally, he ends this lengthy introduction by asking 
Pratensis to urge the workmen who are making him a 
celestial globe and other instruments, so that they can all 
be ready when he comes over again. ^ 

Next comes the account of the star, exactly as afterwards 

^ Perhaps this is an allusion to his having fallen in love about this time, 
as we shall see farther on. 

^ Reprinted in DansJce Magazin, ii. p. 186 (Weistritz, ii. p. 59). 

' This globe is mentioned at some length in the above-mentioned letter 
from Pratensis of April 16, 1573. It must have been a beautiful piece of 
Work, the surface silvered with gilt stars, &c. 


THE NEW STAR OF 1572. 47 

reprinted in his greater work, filling a little more than 
twenty-seven pages (A to second page of D2). As this 
is more generally accessible than the other parts of the 
book, a short abstract will suffice here. Having described 
how he first saw the star, he quotes the words of Pliny 
relating to the star of Hipparchus, which many had taken 
to be a comet ; but as it would be absurd to fancy that a 
great astronomer like Hipparchus should not have known 
the difference between a star of the gethereal region and a 
fiery meteor of the air which is called a comet,-"- it must have 
been a star like the present one which he saw. Since that 
time no similar star has been seen till now, for the star of 
the Magi was not a celestial object, but something relating 
exclusively to them, and only seen and understood by them. 
How it was created he does not profess to oiFer an opinion 
about, but proceeds to treat of its position among the stars. 
This is illustrated by a diagram of the stars in Cassiopea, 
and the measured distances of the new star from a, yS, and 
ly Cassiopese are given,^ after which he shows how the rules 
of spherical trigonometry of Eegiomontanus give the longi- 
tude and latitude of the star from these data. He adds 
that the accuracy of the co-ordinates deduced will, of course, 
depend on that of the positions of the fixed stars he has 
used ; but as he has not any observations of his own to 
depend on, he is obliged to use the positions given by 
Copernicus, trusting that God will spare him and enable him 
to correct the accepted places of the fixed stars by new obser- 
vations. In order to find the distance of the star from the 
earth, he has measured its angular distance from Schedir, 

^ The expression is remarkable, as it shows that Tycho had not yet shaken 
himself free from the old Aristotelean opinion of the comets as atmospheric 

^ Respectively 7° 55', 5° 21, and 5° 1' ; while Progymnasmata, p. 344, gives 
7° 5°'-5. 5° 19') ^°^ 5° 2'. Tycho remarks (ibid., p. 593) that the latter 
results are corrected for the error of excentricity, and were made with the 
improved pinnules which he afterwards adopted. 


whicli passed the meridian nearly at tlie same time, botli at 
upper and lower culmination, and found no difference what- 
ever ; whereas he shows that there would have been a 
parallax at lower culmination equal to 5 8-|' if the star had 
been as near to us as the moon is.'^ Therefore the star 
could not be situated in the elementary region below the 
moon, nor could it be attached to any of the planetary 
spheres, as it would have been moved along with the 
sphere in question in a direction contrary to that of the 
daily revolution of the heavens, while his observations 
show that it has since its first appearance remained im- 
movable. Consequently, it must belong to the eighth 
sphere, that of the fixed stars ; and it cannot be a comet 
or other fiery meteor, as these are not generated in the 
heavens, but below the moon, in the upper regions of 
the air, upon which all philosophers agree, unless we are to 
believe Albumassar, who is credited with the statement 
that he had observed a comet farther off than the moon, 
in the sphere of Venus. Here again Tycho expresses the 
hope that he will some time get a chance of deciding this 
matter (as to the distance of comets) ; but anyhow, he 
adds, this star cannot have been a comet, as it had neither 
the appearance of one nor the proper motion which a comet 
would have been endowed with. 

The third paragraph deals, with the magnitude and colour 
of the star. The volume of a star is very considerable; the 
smallest are eighteen times as great as the earth, those 
of the first magnitude 105 times as great. Therefore the 
new star must have been of immense size. He then 
describes its gradual decline, until it " now, at the beginning 
of May, does not exceed the second magnitude." It must, 

^ He assumed that the parallax would be — o at the upper culmina.tiou, 
but in his later work he remarks that this is a mistake, and that it would be 
nearly 7'. 

THE NEW STAR OF 1572. 49 

therefore, at first have been mucli more than a hundred 
times as large as the earth, but it has decreased in size. 
It twinkles like other stars, while the planets do not 
twinkle, which is another proof of its belonging to the 
eighth sphere. Having mentioned the change in colour, 
he finishes the astronomical part of the treatise on the star 
by remarking that the change in colour and magnitude 
does not prove it to be a comet or a similar phenomenon, 
for if it is possible that a new body can be generated in 
the sethereal region, as he has proved to be the case in 
opposition to the opinions of all philosophers, it must be 
considered far less impossible and absurd that this new star 
should change in brightness and colour. And if it could 
ever, beyond the ordinary laws of nature, have been seen in 
the heavens, it would not be more absurd if it should again 
cease altogether to be visible, though again in opposition to 
those laws. 

Tycho now proceeds to give his opinion about the astro- 
logical effects of the new star.-' These cannot be estimated 
by the usual methods, because the appearance of the star is 
a most unusual phenomenon. The only known precedent 
is the star said to have appeared at the time of Hipparchus, 
about B.C. 125. It was followed by great commotions 
both among the Jewish people and among the Gentiles, 
and there is no doubt that similar fatal times may be ex- 
pected now, particularly as the star in Cassiopea appeared 
nearly at the conclusion of a complete period of all the 
Trigoni.^ For in about ten years the watery Trigon will 

1 Pol. D. 2 verso to E. 3. 

^ As some readers may not be familiar with the phraseolog}' of astrology, 
it may be well to mention here that each Trigonus consists of three signs of 
the Ecliptic, 120° from each other ; the four Trigoni correspond to the four 
elements, and each of them is in turn the ruling one, until a conjunction of 
planets has taken place within one of its signs. In about 800 years the four 
Trigoni will all have had their turn, and a cycle is completed. See, e.g., 



end with, a conjunction of tlie outer planets in the end of 
the sign of Pisces, and a new period will commence with 
a fiery Trigon. Eeferred to the pole (i.e., according to 
right ascension), the new star belongs to the sign, of 
Aries, where the new Trigon will also begin, and there will 
therefore be great changes in the world, both religions and 
political. The star was at first like Venus and Jupiter, 
and its effects will therefore first be pleasant ; but as it then 
became like Mars, there will next come a period of wars, 
seditions, captivity, and death of princes and destruction 
of cities, together with dryness and fiery meteors in the 
air, pestilence, and venomous snakes. Lastly, the star 
became like Saturn, and there will therefore, finally, come 
a time of want, death, imprisonment, and all kinds of sad 
things. As it is not exactly known when the star first 
appeared, he follows the example of Halus, a commentator 
of Ptolemy (on the occasion of the appearance of a comet), 
and assumes that it appeared at the time of new moon, 
the 5th of November,-^ at yh. 5 5m., for which moment he 
finds that Mars was the ruling planet. The places most 
affected by the star will be those in latitude 62° (in the 
zenith of which the star could be) ; but as the star belongs 
to Aries, its influence will be felt nearly over the whole of 
Europe, and particularly after the great conjunction (of 
April 1583) has added its great power to that of the 

It will be seen that this prediction is only expressed in 
very vague terms, and we shall find, when we come to analyse 

Cyprianus Leovitius, De Conjwnctionihus Magnis^ London, 1573 ; Kepler, De 
Stella Nova, 1606, p. 13 {Opera Omnia, ii. p. 623) ; Ideler, Sandbuch der 
Chronologie, ii. p. 401. More about this in Chapter VIII. 

^ No doubt he was right, as this would be a capital day for a celestial 
explosion to take place I The date and time of the first appearance was 
required to prepare the horoscope of the star in the usual manner (see below. 
Chapter VI.). 

THE NEW STAR OF 1572. 51 

Tycto's later writings, that lie afterwards modified and ex- 
tended it. When he wrote his preliminary treatise on the 
new star, he was evidently chiefly inclined to ascribe a direct 
physical and meteorological influence to the celestial bodies, 
though he was by no means blind to the difficulty of fore- 
telling the results of this influence, but he became gradually 
more inclined to disregard the physical effect (dryness, pesti- 
lence, &c.), and solely to look to the effect of the stars on 
the human mind, and through that on the human actions. 
That an unusual celestial phenomenon occurring at that 
particular moment should have been considered as indicatiag 
troublous times, is extremely natural when we consider the 
state of Europe in 1573. The tremendous rebellion against 
the Papal supremacy, which for a long time had seemed 
destined to end in the complete overthrow of the latter, 
appeared now to have reached its limit, and many people 
thought that the tide had already commenced to turn. In 
the south of Germany and in Austria the altered tactics of 
the Church of Rome, due to the influence of the fast risiag 
Society of Jesus, were stamping out the feeble attempts of 
Reformers ; in Prance, the Huguenots were fighting their 
unequal battle with the fury of despair against an enemy 
who a year ago had attempted to end the strife by the 
infamous butchery of St. Bartholomew ; ^ in. the Nether- 
lands, hundreds had suffered for their faith, while the country 
was being devastated with fire and sword in the vain efibrts 
of the Spanish Government to make a free nation submit 
to their own sanguinary religion ; in England, the hopes of 
Protestants might at any moment be seriously threatened if 
the dagger of an assassin should find way to the heart of 
their queen, or if her most formidable and venomous enemy 
should turn his dreaded power against her. Who could 

^ The year 1572 was, according to the custom of the age, remembered by 
the line " LVtetIa Mater sVos natos DeVoraVIt." 


doubt that fearful disturbances were in store for the genera- 
tion that beheld the new star as well as for the following 
one ? The moderation of Tycho's astrological predictions is 
therefore remarkable, and becomes more conspicuous if we 
compare his opinions with the many silly ones expressed by 
contemporary writers. 

Before we say a few words about these, we shall, how- 
ever, finish the review of the contents of Tycho's book. 
"We have already mentioned that he did not think it worth 
while to print the astrological calendar for the year 1573, 
of which the treatise on the new star originally formed a 
part, but that he contented himself with publishing the 
introduction, setting forth the principles on which the 
calendar, or diary, as he calls it, had been constructed. 
This fills sixteen and a half pages. It begins with a good 
deal of abuse of the ordinary prognostications, the absurdi- 
ties of which he intends to expose in a book to be called 
Contra Astrologos pro Astrologia. This intention he does 
not seem to have carried into effect, and two other treatises, 
which he says were already written, seem not to have 
been preserved.-*- He remarks that both the Alphonsine 
and the Prutenic Tables are several hours wrong -with regard 
to the time of the equinoxes and solstices, and it is use- 
less to give the time of entry of the sun into any part of 
the Zodiac to a minute, as the sun in an hour moves 
less than 3', a quantity which cannot be observed with 
any instrument. Some writers are foolish enough to give 
minutes and seconds when stating the time of any particular 
position of a planet, although at the conjunction of Saturn 
and Japiter ia 1563 the Alphonsine Tables were a whole 

1 One of these was Dc rariis Astrologorum in Ccelestium Domorum Divisvme 
Opinionibiis, earumque Insufficientia, in which he proposed a new plan of 
dividing the heavens into " houses " by circles through the points of inter- 
section of the meridian and horizon. The other treatise was De Horis 
Zodiaci incegualibus, quas Planetarias vacant. 

THE NEW STAE OF 1572. 53 

month in error, wliile even the Prutenic Tables could hardly 
fix the day correctly, not to speak of minutes or seconds.'- 
A calendar should contain the usual information as to the 
aspects, time of sunrise and sunset, time of rising and 
setting of the moon and planets, and the names of the 
principal stars rising and setting at the same time. The 
moon is of particular importance as it is nearest to the 
elementary world, but even the planets must influence the 
weather. Lastly, a calendar should give the probable 
weather for every day, concluded from the configurations of 
the celestial bodies. He would warn the reader not to expect 
too much from the weather predictions, partly because much 
remains yet to be done in exploring the motions of the 
stars and their effect, partly on account of the fluidity of 
the inferior matter, which sometimes delays, sometimes 
hastens the effect produced by the stars. But any blame 
should rest on him and not on the art. Besides terrestrial 
influences must act differently in difierent parts of the earth, 
so that one configuration of the stars cannot have the same 
effect in several localities. Therefore he has undertaken 
this work principally in order by observation to learn the 
effect of the stars on this part of the earth, so that our 
posterity may profit thereby, and in order to secure this 
object he exhorts all meteorologists to take observations of 
the weather. 

The only part of the diary given in the book is that 
relating to the total eclipse of the moon on December 8, 
1573. It fills twenty-four pages, including two full-page 
woodcuts — one of the progress of the eclipse, the other of 
the earth, moon, and planets at that time. He gives first 
the calculation of the eclipse by the Prutenic Tables, with all 

' audaces astronomos, exquisites & subtiles caloulatores, qui Astro- 
nomiam in Tnguriis & popinis, vel post fornacem, in libris & chartis, non 
in ipso coelo (quod par erat) exercent. Plerique enim ipsa sidera (pudet dioere) 
ignorant. Sic itur ad astra " (fol. G.). 



the details step by step, and for the sake of comparisoD, 
the resulting time of the various phases (without details of 
calculation) by the Alphonsine Tables and Purbach's Tables ; 
also the same data after correcting the places of the sun and 
moon by his own observations.-*- He adopts the meridian 
35° ab occasu, by which he probably means 35° east of 
the peak of Teneriffe. He recommends observers to discard 
clocks of any kind, but to fix the time by observing alti- 
tudes of some stars not too far from the east or west 
horizon, but which, when on the meridian, would have a 
considerable altitude, and he gives the altitudes of a few 
stars for the beginning and end of the eclipse and of 
totality. The astrological significance he computes by the 
rules given by Ptolemy in the second book of his Tetrabiblion, 
Mercury, and in the second place Saturn, are the ruling 
planets. The former means robbery, stealing, and piracy ; the 
latter want, exile, and grief. The regions chiefly affected 
by the eclipse are those which Ptolemy specially connected 
with the sign of Gemini, where the moon is. These are 
Hircania, Armenia, Cyrene, Marmaria, and Lower Egypt, 
to which later astrologers have added Sardinia, Lombardy, 
Flanders, Brabant, and Wlirtemberg. It has been observed 
that the sign of Gemini has a special significance for 
Niimberg whenever an eclipse or a conjunction took place 
in it, and the Niirnbergers may therefore expect some- 
thing, possibly pestilence, as Gemini is a "human sign," 

^ It may not be -without interest to insert these data here : — 

Tabulse Prat. 

Ex propria 
Motuum ratione. 

Initium primse obscurationis . 
Initium totius obscurationis 


Finis totius obscurationis . 
Finis ultimsB obscurationis 
Locus in Sagit. .... 

H. M. S. 

5 55 41 

6 59 5° 

7 51 29 

8 43 8 

9 47 17 
26° 29' 

H. M. 

6 IS 

7 20 

8 10 

10 5 
26° 40' 

THE NEW STAR OF 1572. 55 

and also on account of the positions of Mercury and Mars. 
Countries whose rulers were born when Gemini was cul- 
minating may also be on the look-out, and generally speak- 
ing kings and princes are more affected by eclipses than 
private people ("as I have observed myself "), because the 
sun and the moon are the princes among the planets. The 
effect will last as many months as the eclipse lasted hours, 
and the beginning of it depends on the moon's distance 
from the horizon at the commencement of the eclipse. 
This eclipse will take effect from March till July 1574 (for 
latitude 56°). As examples of this kind of prognostica- 
tions he quotes several recent eclipses. First, the lunar 
eclipse of April 3 , 1558, after which Charles V. died ; then 
the solar eclipse of April 18, 1558, which did not begin 
to take effect till the end of the year, and then Christian 
III. of Denmark and Norway died ; and shortly afterward 
the deposed king, Christiern II., a captive for many years, 
died also ; and Tycho shows how beautifully this agreed 
with their horoscopes. On November 7, 1565, a lunar 
eclipse took place near the Plejades, a group of stars with 
a moist and rainy influence, and consequently rainy weather 
came on, as he had at the time predicted at Leipzig. 
Similarly a lunar eclipse occurred on the 28th October 
1566 close to Orion, and the effect should, according to 
Ptolemy, begin at once ; and so it did, and the whole winter 
turned out wet, as he predicted himself at Eostock. He 
does not say a word about the old Sultan ! 

The book is wound up with In Vraniam EUgia Autoris, 
filling more than eight pages, and a page of verses by 
Vedel. In the Megy, Tycho promises soon to produce 
something better, as neither the sneers of idle people nor 
the hardships of study shall deter him ; let others boast of 
their achievements in war or of their ancient family, let 
others seek the favour of princes or hunt for riches, or waste 


their time gambling and hunting, he does not envy them, 
for though sprung from ancient races both on the father's 
and on the mother's side, he does not value it, and calls 
nothing his but what has originated with himself.^ But 
his mind is planning great things, and happy above all men 
is he who thinks more of celestial than of earthly things. 

I have given a very full account of the contents of Tycho's 
little book, not only because it is now extremely scarce, but 
also because it is very characteristic of him, and presents 
us with a perfect picture of the young author, his plans and 
his difficulties. We see him thoroughly aware of the great 
desideratum of astronomy, a stock of accurate observations, 
without which it could not possibly advance a single step 
further, and hoping that life and means might be granted 
him to supply this deficiency ; we see in him at the same 
time a perfect son of the sixteenth century, believing the 
universe to be woven together by mysterious connecting 
threads which the contemplation of the stars or of the 
elements of nature might unravel, and thereby lift the 
veil of the future ; we see that he is still, like most of 
his contemporaries, a believer in the solid spheres and 
the atmospherical origin of comets, to which errors of the 
Aristotelean physics he was destined a few years later to 
give the death-blow by his researches on comets ; we see 
him also thoroughly discontented with his surroundings, and 
looking abroad in the hope of finding somewhere else the 
place and the means for carrying out his plans. At the 
same time the book bears witness to the soberness of mind 
which distinguishes him from most of the other writers on 
the subject of the star. His account of it is very short, but 
it says all there could be said about it — that it had no 
parallax, that it remained immovable in the same place, 

' " Nil tamen his moveor. Nam qvse non fecimus ipsi 
Et genus et proavos, non ego nostra voco." 

THE NEW STAE OF 1572. 57 

that it looked like an ordinary star — and it describes the 
star's place in the heavens accurately, and its variations in 
light and colour. Even though Tycho made soine remarks 
about the astrological significance of the star, he did so in 
a way which shows that he did not himself consider this 
the most valuable portion of his work. To appreciate his 
little book perfectly, it is desirable to glance at some of the 
other numerous books and pamphlets which were written 
about the star, and of most of which Tycho himself has in 
his later work (Progymnasmatd) given a very detailed analysis, 
devoting nearly 300 pages to the task. It would lead us 
too far if we were to follow him through them all, but it 
will not be without interest briefly to describe what some of 
the more rational of his contemporaries published about the 
star, and to what absurdities a fervid imagination led some 
of the common herd of scribblers. 

At Cassel the star was observed by Landgrave Wilhelm 
IV., an ardent lover of astronomy, of whom we shall hear 
more in the sequel. He did not hear of the star till the 
3rd December, and took observations of its altitude in 
various azimuths from that date and up to the 14th March 
following. From the greatest and smallest altitude Tycho 
found afterwards a value of the declination differing less than 
a minute from that found by himself. From the azimuths 
and altitudes observed at Cassel Tycho deduced the right 
ascension and declination : the single results for the latter 
are in good accordance inter se, while those for right ascen- 
sion differ considerably, the greatest difference being more' 
than 2°. Tycho justly concludes that this must be caused 
by the bad quality of the clock employed by the Landgrave, 
who merely gave the time of observation in true solar time, 
without famishing the means of correcting for the error of 
his clock. In a letter to Caspar Peucer, the Landgrave 
stated that the star might have a parallax not exceeding 3', 


as there was that difference between the polar distances 
above and below the pole ; but his instruments had at that 
time not reached the degree of accuracy which they did ten 
years later, and the difference is not surprising. Peucer 
and Wolfgang Schuler at Wittenberg found a parallax of 
1 9', which Tycho believed was a consequence of their having 
used an old wooden quadrant ; and, in fact, when he learned 
that the Landgi-ave had found little or no parallax, Schuler 
had a large triquetrum constructed, and also found that the 
star had no parallax, or at most a very small one.^ Many 
observers measured the distance of the new star from the 
neighbouring ones, but the results found were generally 
considerably in error. Thus the Bohemian, Thaddseus 
Hagecius, physician to the Emperor, in an otherwise sensible 
book,^ gives a number of observed distances, some of which 
are 7' to 12' (one is even 16') wrong, and even the English 
mathematician, Thomas Diggs (or Digges), who had made 
a special study of the cross staff, and had his instrument 
furnished with transversal divisions, differed i^' to 4' from 
Tycho, — possibly, as the latter thinks, because he did not 
allow sufficiently for the error of excentricity.* CorneHus 
Gemma, a son of the well-known astronomer. Gemma 
Erisius, and professor of medicine at Louvain, had a great 

' The triquetrum had been much in use from the time of Ptolemy, It con- 
sisted of two arms of equal length and movable round a hinge, while a third 
and carefully graduated arm gave the means of measuring the angle between 
the two former by the aid of a table of chords. 

^ " Dialexis de novee et prius iucognitae Stellse invsitatse Magnitudinis et 
splendissimi Luminis Apparitione et de eiusdem Stellae vero loco constituendo. 
Per Thaddaeum Hagecium ab Hayek." Pranoofurti, a. M. 1574. 176 pp. 4to. 
In an appendix are two papers on the star by Paul Pabricius and Corn. 
Gemma. Some years after Hagecius sent Tycho a copy with many MS. 
corrections and additions, which Tycho quotes extensively in his Progymna^- 
mata (p. 505 et seq.). In this corrected copy the most erroneous measures had 
been improved or struck out, whereby the greatest differences from Tycho's 
results were reduced to 4' or 6'. 

' "Alaa seu Soalse Mathematicae, quibus visibilium remotissima Ccelorum 
Theatra conscendi, et Planetarum omnia itinera novis et inauditis methodis 
explorari . . . Thoma Diggeseo authore. " Londini, 1573- 4to. 

THE NEW STAE OF 1572. 59 

deal to say about the star, but most of his distance measures 
are upwards of a degree wrong. On the other hand, 
Michael McBstlin, the teacher of Kepler, though he possessed 
no instruments, determined the place of the star with fair 
accuracy simply by picking out four stars so placed that the 
new star was in the point of intersection of two lines drawn 
through two and two of them. As the star did not move 
relatively to these four stars during the daily revolution of 
the heavens (of which he assured himself by holding a 
thread before the eye, so that it passed through the three 
stars), Moestlin concluded that it had no parallax, and that 
it was situated among the fixed stars, whose distance Co- 
pernicus, of whom he was a follower, had shown to be 
extremely great. Digges tried the same method, using a 
straight ruler six feet long, which he first suspended verti- 
cally until he found two stars which were in the same 
vertical as the new star ; six hours afterwards he tried 
again, holding the ruler in his hand, whether the three 
stars were still in a straight line. He found the star to be 
exactly in the point of intersection of the line joining ^ 
Cephei and y Cassiopese, and the line joining i Oephei and 
8 Oassiopese, and concluded that it could not have a parallax 
amounting to 2'. Tycho afterwards computed the pilace of 
the star from these data, using his own accurate positions of 
the four stars, and found the longitude only 2' greater and 
the latitude ^' greater than what he had deduced from his 
own observations.'' Digges had hoped to test the Coper- 
nican theory of the motion of the earth by trying whether 
the star had an annual parallax, but he could find none. 

' Digges, I.e., chapter x., fol. K 3. By a mistake he says that the two lines 
join 5 Cassiopese, /3 Cephei, and 1 Cephei, 7 Cassiopese. Tycho remarlis that 
one can see at a glance that these two lines do not intersect each other between 
the stars, but pretending not to see that it is merely a lapsus calami, he gravely 
calculates places from these data, using his own distances, and of course gets 
absurd results {Progymn., p. 681), after which he interchanges the stars, and 
gets the correct result given above. 


The question of the staa-'s distance from the earth being one 
of special interest, all observers tried to determine the daily 
parallax:, but the results varied immensely according to the 
skill of the observer. While several writers, in addition to 
those already mentioned, state that they could find no per- 
ceptible parallax,^ others found a large one. Thus EHas 
Camerarius at Frankfurt on the Oder had at first thought 
that he had found a parallax of 12', but in January 1573 
he could only find one of 4 J', from which he concluded that 
the star had in the meantime receded from us in a straight 
line (so that its apparent place was not altered), and that 
this was the cause of its diminished brightness. A German 
writer of the name of Nolthius tried to find the parallax by 
a method suggested by Eegiomontanus from the hour angle, 
the azimuth and the latitude of the observing station, com- 
paring the altitude computed from these with the observed 
one. He chose, however, a bad time for the experiment, 
when the altitude was very great {77°), and it is not to be 
wondered at that he found an absurd result — 39' for the 
parallax — and it does not seem to have struck him that this 
would correspond to a parallax equal to 2° 42' at the lowest 
altitude of the star, which could not have escaped even 
casual observers, as pointed out by Tycho.^ 

Of greater interest than these crude attempts are the 
statements of the various writers as to the time when the 
star first became visible. Some writers say that the star 
was already seen early in October, but none of them are 
entitled to much credit. The above-named Elias Camerarius 
at Frankfurt on the Oder says that it appeared " in principio 
Octobris Anni 1572 uesperi circa horam. i O prope Meridi- 

^ Thus Paul Fabricius at Vienna, Hainzel (using the great quadrant at 
Augsburg), Reisaoher at Vienna, Com. Gemma (not stating how found), 
Hierouimus Munosius at Valencia, Valesius from Covarruvias (physician to 
Philip n. of Spain), and Johan Praetorius (Richter), professor at Wittenberg. 

* Progymn., i. p. 760. 

THE NEW STAPv OF 1572. 61 

anum ; " but as he appears to be utterly unknown in the 
history of science, too much weight ought not to be attached 
to his unsupported statement.'' Annibal Eaimundus of 
Verona (of whom we shall hear more presently) tells us that 
the star was seen " circa principium Octobris, a plurimis 
Nobilibus et Ignobilibus, eruditis atque indoctis," but further 
on he contradicts himself, saying that the star has now been 
visible three months, and as he wrote at the end of January 
1573, this would make the appearance of the star date 
from the end of October or the beginning of November.^ 
A little French book, published in 1590, states that the 
star was seen " au mois d'Octobre " in Spain by shepherds 
keeping watch over their flocks, but this reminds one too 
much of the words used by St. Luke, and is contradicted by 
other testimony.^ According to Paul Fabricius at Vienna 
it appeared "sub Octobris finem."* All these statements 
are contradicted by Munosius, professor ia the University of 
Valencia, who maintained that he was certain the star had 
not yet appeared on the 2nd November, as he was showing 
his pupils the constellations on that night, and could not 
have" failed to see it, and Spanish shepherds agreed with 
him therein. As Munosius took very fair distance measures 
of the star, and wrote in a sensible strain, there is every 
reason to believe him.' The first trustworthy observation 

^ Ibid., p. 692. Tycho never saw the book, and only knew it from a MS. 
abstract made for him by Hagecius. It is in the Poulkova Library, and 
W. Stmve mentions that the writer states in two places that he saw it 
"principio Octobris." Astron. Nachr., xix. p. 334. Elias Oamerarius is not 
mentioned in Jocher's Gdehrten Lexicon, nor in any other historical work 
that I have at hand. 

" Progym., i. pp. 721-723. Tyoho remarks that Raimundus has forgotten 
the proverb that liars should have a good memory, 

^ La nomdle Estoille apparve svr tous Us Climats dv Monde : Et dc ses effects. 
Paris, 1590. 28 pp. small 8vo. This book was not known to Tycho Brahe. 

* Hagecii Dialexis, p. 129. Tycho remarks {Progyni., p. 548) that if it had 
been visible in October, Moestlin (who saw it "the first week in jSTovember") 
would probably have noticed it. 

5 Progymn., i. pp. 565, 566. 


seems to have been made by Wolfgang Schuler at Witten- 
berg, who says that he saw it at six o'clock in the morning 
on the 6th November.^ On the 7th at 6 p.m. it was seen 
by Paul Hainzel,^ and the same evening by Bemhard 
Lindauer, minister at Winterthur in Switzerland.^ Mau- 
rolycus, the well-known astronomer at Messina, and David 
ChytrEeus at Eostock, saw it on the 8th.* Many writers 
have quoted the words of Cornelius Gemma, stating that the 
star appeared first on the 9th November, and that it had 
not been visible on the previous evening in clear weather,* 
but they have overlooked the fact that Gemma, in his 
book Be Natures Divinis Characterismis, seu raris & admi- 
randis Sjiecf aculis, Jjihri ii. (Antwerp, 1575, 2 vols. 8vo), 
tells quite a different story, viz., that some people had 
already seen it before the end of October. He does not 
say when he first saw it himself, but he did not begin to 
observe its position till the 26th November, as he thought 
it idle talk when he first heard of a new star.® ' Gemma's 

■^ Progymn., i. p. 621. " Ibid., p. 536. 

' Rudolf Wolf in Astr. Nachr., Ixv. p. 63. 

^ About the observation of Maurolyeus, see Nature, xxzii. p. 162 (June 18, 
1885). About Chytrseus, see R. Wolf, Geschichte der Astronomic, p. 415. 

^ " Nona Nouembris, die Dominieo vesperi, cum tamen obseruautibus proxi- 
mum coeli locum die octauo, etiam sereno iethere non apparuerit" (Hageni 
Dialexis, p. 137), also in his separate pamphlet, "Stellae PeregriuiE iam 
primum exortse et Coelo constanter hserentis tpaivifievov , . ■ , per D, Cor- 
nelium Gemmam." Lovanij, 1573. 13 Pp. 4to (fol. A2). There is one re- 
print (s.a.e.l.) of this, with some omissions, and coupled with a paper by 
Postellus, and another coupled with a reprint of a paper by Cyprianus Leo- 
Tltius. Among writers who have quoted Gemma may be mentioned Newton 
(Principia, iii., ed. Le Seur and Jacquier, p. 670), who thought that Gemma 
himself had looked at the sky on the Sth without seeing it ; but this was a 
mistake, as we have just shown above. 

^ Gemma's book is a very curious one. The first volume is about terrestrial 
curiosities, Siamese twins, and much queerer beings (well illustrated) ; vol. ii. 
is about celestial wonders, comets, &c., chapter iii. being "De prodigioso 
Phsenomeno syderis noui" (pp. 111-155). Page 113 : "Sed qui se primos ob- 
seruasse voluerunt, nonum diem pro initio tradiderunt : cum tamen interea 
conuenerim plures, quorum alij diem secundum aut tertium annotarint, 
plerique vel ante Octobris finem ferant etiam a vulgaribus obseruutum. . . . 
Primum observationis tempus fuit nobis die Nou. 26." 

THE NEW STAR OF 1572. 63 

testimony is therefore worth nothing, and it may safely be 
assumed that the star became visible between the 2nd and 
the 6th of November, and was seen by an apparently trust- 
worthy observer on the morning of the 6th. 

That many different attempts should be made to explain 
the nature of the new star and the cause of its sudden 
appearance is very natural. Most writers contented them- 
selves by saying that it was some sort of a comet, though 
not of the usual kind, as these, according to Aristotle, 
were sublunary, while the star was far beyond the moon. 
That it did not in the least look like a comet was generally 
not considered an objection to this theory, as instances 
could be quoted of comets having appeared without tails ; ^ 
a greater difficulty was the absence of motion relatively to 
the other stars in Cassiopea, as only very few writers had the 
hardihood to maintain that it had actually moved before it 
disappeared.^ Gemma sought to explain this by supposing, 
with Elias Camerarius, that the star was moving in a 
straight line away from us,^ but this could not account 
for the sudden appearance of the star with its maximum 
brightness. Others thought it more probable that the star 
was not a new one, but merely an old and faint star, which 
had become brighter through some sudden transformation 

■^ In a pamphlet, " La Declaration d'vn comete ou estoille prodigieuse 
laqvelle a commence a nous apparoistre b, Paris, en la partie Septentrionale 
du ciel, an mois de Nouembre dernier en I'an present 1 572, & se monstre 
encores auionrd'huy. Par I. G. T>. V.," Paris, 1572, 4to, 8pp., it is said that 
people who had good sight could see several rays, of which the longest, which 
might be called the tail of the comet, was always turned to the east ! Its 
distance from the pole-star, when above the pole, was "le plus souvent " 
25° 30', but afterwards it became 24° 40', and below the pole 24° 30', which 
the author takes to be the effect of parallax I The author was probably Jean 
Gosselin de Yize, librarian to the King. The pamphlet was not known to 
Tycho ; it is not in Lalande's BihUograpMe. 

^ Leovitius, writing in February 1573, says it seems to him that the star 
had during the last month moved three degrees towards the north I 

3 The English astronomer, John Dee, was of the same opinion {Proffymn,, 
p. 691). 


of tke air between it and tlie earth, or a condensation of 
part of one of the spheres through which its light had to 
pass. The principal reason why some writers {e.g., Eeisacher 
and Vallesius) adopted this explanation was, that God had 
ceased creating on the sixth day, and nothing new had been 
made since then. Eeisacher had at first thought that the 
star was identical with « Cassiopese, which had merely 
become brighter, but when the light of the star had become 
less dazzling he perceived that k was still in the heavens, 
and that he had merely failed to see it hitherto owing to 
the overpowering light of the new star. More obstinate 
was Eaimundus of Verona, who in two publications main- 
tained that it was nothing but k. He seems to have done 
so with unnecessary heat, and using contemptuous expres- 
sions about people who thought differently, as Tycho in 
reviewing his writings uses stronger language than usual, 
and Hagecius thought it necessary to publish a refutation 
full of the most violent invectives and written in a very 
slashing style. ■*■ Another Italian, Frangipani, also took the 
star to be « Cassiopeee, and as its place did not agree with 
that assigned to the latter by Ptolemy, he calmly assumed 
that the old star must have moved. He quotes the old 
story about the seventh star of the Plejades (Electra) hav- 
ing disappeared after the destruction of Troy, and asserts 
that the pole-star did the same for a while after the taking 
of Constantinople by the Turks. ^ All this is, however, very 
tame compared with the fancies of a German painter, Georg 
Busch, of Erfurt, who wrote two pamphlets " Von dem 
Cometen." According to him it was a comet, and these 
bodies were formed by the ascending from the earth of 
human sins and wickedness, formed into a kind of gas, 

^ "ThaddcEJ Hageoij ab Hayek, Aulas Cesarefe Medici, Responsio ad viru- 
lentum et maledicum Hannibalis Raymundi Scriptum," &o. Pragse, 1576. 

2 Progymnasmata, p. 743. 

THE NEW STAR OF 1572. 65 

and ignited by the anger of God. This poisonous stnfF 
falls down again on people's heads, and causes all kinds of 
mischief, such as pestilence, Frenchmen (!), sudden death, 
bad weather, &c. Perhaps it was the night of St. Bartho- 
lomew which made Busch think of Frenchmen in this 

The question as to whether new stars had ever appeared 
before was touched on by several writers, who referred to 
the star of Hipparchus and the star of Bethlehem. Land- 
grave Wilhelm IV., in his letter to Peucer, also alludes to 
the star stated by Marcellinus to have appeared a.d. 389.^ 
Cyprianus Leovitius states that similar stars appeared in 
the same part of the heavens in the years 945 and 1264, 
the " comet " of the latter year being without a tail and 
having no motion, and says that this information was taken 
from an old manuscript.^ It is certainly a very suspicious 
circumstance that real comets appeared both in 945 and 
in 1264, and the absence of tail and motion might merely 
be subsequent embellishments by the writer of the manu- 
script referred to by Leovitius ; but, on the other hand, it is 
quite possible that new stars may have appeared in those 

' About this star see Calvisii Opus Chronologicum, p. 413 (second edit., 
1620), and Tlie Observatory^ vii. p. 75. 

2 " De Nova Stella. Judicium Cypriani Leovitii a Leonicia, Mathematici, de 
nova Stella siue cometa, viso mense Nouembri ac Decembri A.D. 1572. Item 
mense Januario & Februario A.D. 1573. Lavingee ad Danubium, 1573." 4to, 
8 fol. : — " Historise perhibent tempore Ottonis primi Imperatoris, similem 
stellam in eodem fere loco Coeli arsisse, A.D. 945. "Vbi magnse mutationes 
plurimaque mala, uarias Prouincias Europae peruaserunt, potissimum propter 
peregrinas gentes infusas in Germaniam. Verum multo locupletius testi- 
monium in hiatorijs extat de A.D 1264, quo Stella magna & lucida in parte 
Coeli Septentrional! circa Sjdus Cassiopeae apparuit, carens similiter crinibus, 
ao destituta motu suo proprio.. " In the margin, opposite the date 1264, is : 
"Descriptio huius Cometse desumpta est ex antique codice, manu scripto. 
Euentus hi congruent cum significationibus stellae propositiE : quod bene 
notandum est : videoque hio aliquid insigne. " Tycho lias reprinted the whole 
pamphlet (pp. 705-706), leaving out the "Judicium breve" at the end, and 
also the marginal notes. The latter are also omitted from a reprint pub- 
lished (s. 1.) in 1573, together with a reprint of Gemma's pamphlet. 



years witliout being noticed by other clironiclers, as science 
was then at it its lowest ebb in Europe, and a new star of 
perhaps less than the first magnitude and of short dura- 
tion (like the stars of 1 866 and 1876) could easily escape 
detection.-^ The only other contemporary author who 
alludes to the years 945 and 1264 is Count Hardeck, who 
in 1573 '"'3'S Rector of the University of Wittenberg ; but 
as his little book is dated the i st May 1573, and that of 
Leovitius the 20th February, he would have had time to 
copy from Leovitius, and in any case it is certain that he 
speaks of a real comet of the year i 2 64, as he mentions 
its tail, while it is doubtful whether he means a comet or a 
star when speaking of 945.^ It has been repeatedly sug- 
gested that the star of Cassiopea might be a variable star, 
with a period of about three hundred years, in which case 
it should again become visible about the present time, but 
it is needless to say that the vague assertions of Leovitius 
form a very slender foundation on which to build such a 

' According to Klein, Der Pixsternhimmel, p. 102, the Chronicle of Alhertus 
Stadensis (Oldenburg) mentions a bright star in Capricornus in 1245 (not 
alluded to elsewhere), as bright as Venus, but more red, and which lasted for 
two months. 

2 " Orationes duae. Vna de legibus et disoiplina. Altera de Cometa 
inter Sidera lueente in mensem septimum, continens oommonefactionem de 
impendentibus periculis. A Joh. Comite Hardeci. Wittenberg, 1573." 8vo. 
Fol. C, p. 2 : — "Reperimus Cometas qui ante haeo tempora in eodem octaui 
orbis loco fulserunt, fere gentes coneitasse Boreas, suis excitas sedibus, 
ad quserendas nouas. Qui Honorij principatu conspectus est, cuius meminit 
Claudianus, baud dubie finem Imperio occidentis cum tristi ac horribili ruina 
attulit . . . Qui Ottone primo imperante ad eandem Cassiopseam flagrauit 
Cometa, Vngaros in Germaniam, Ottonem in Italiam impulit . . . Qui anno a 
nato Christo sexagesimo supra millesimum ducentesimum ibidem luxit inter- 
regni tempore, coma ad coeli medium usque dispersa, Carolum Andegauensem 
e Gallia, per furiosa & scelerata consilia dementis Pontificis attraxit in 
Italiam." This book is not mentioned by Tycho Brahe. In his Cometo- 
graphia, p. 817, Hevelius quotes Christianus as mentioning the star of 945. 
This may seem to some readers to refer to the Chronicle of Christianus of 
1472 {Pvlkova Cat., p. 76), but, as Professor Copeland has pointed out to me, 
it is merely a quotation of D. Christiani Tractatus de Cometarujn Essentia, 
1653, and therefore it does not prove anything as to the correctness of tte 
statement of Cyprianus. 

THE XEW STAR OF 1572. 67 

theory. All tlie samej it is desirable tliat tLe place where 
the star of 1572 appeared should be examined from time 
to time. Argelander has, from a discussion of all Tycho's 
distance-measures, found the most probable position of the 
star for the equinox of 1865 to be: EA=oh. 17m. 20s., 
Decl. = +63° 23'.9. This position agrees remarkably well 
with that of a small star of the lo.i i magnitude, No. 129 
of D' Arrest's list of stars in the neighbourhood of Tycho's 
Nova, which is for 1865 : oh. 17m. 193.-1-63° 23'.!. 

Whether this small star is variable or not must be left 
for the future to decide. Argelander stated in 1864 
(speaking from memory) that he had about forty years pre- 
viously failed to see any star in the place with the transit 
instrument at Abo (of 5-2 inches aperture), and that he had 
also later — probably in 1849 — been unable to see anything 
with the transit circle at Bonn.-^ There is thus a possibility 
that D'Arrest's star may have increased in light of late years, 
and observations made at Twickenham by Hind and W. 
E. Plummer in 1872—73, and at Prague by Safarik 
in 1888-89, seem to indicate that it is subject to very 
slight fluctuations of light. ^ The map of all the stars in 
the neighbourhood, prepared by D' Arrest (which is com- 
plete down to the fifteenth or sixteenth magnitude, within 
a radius of i o' from the place of the Nova) may ia future 
be compared with photographs of this interesting spot, 
which deserves to be watched from time to time. 

' D'Arrest, Oversigt over det Tcgl. SansJce Vidensh Selshahs ForhandMnger, 
1864, p. I, where a list of stars near the place and a map are given. Micro- 
metric observation of the star No. 129 in Astr. Nachr., vol. Ixiv. p. 75. 
Argelander, Ueber den neuen Stern vom Jahre 1572, Astr. Nachr,, vol. 
Ixii. p. 273. 

' Monthly Notices, B. Astr. Soc., xxxiv., p. 168 ; Astr. Nachr., vol. 
cxxiii. p. 365. D'Arrest in 1863-64 found no variability. The place was 
already examined by Edward Pigott between 1782 and 1786, but without 
finding any variable star {Phil. Trans., 1786) ; it was first photographed by 
Mr. Roberts in 1890 (Monthly Notices, L. p. 359). 


I shall not liere enter into a lengthy examination of the 
various prognostications and more or less wUd speculations 
to which the new star gave rise in 1572. As remarked 
by Tycho, the usual methods of astrology were of no avail 
in this exceptional case, aaid there is therefore little to be 
gained even to the student of the history of astrology (a 
subject of considerable interest) by an examination of the 
literature on the star. I shall only point out a few curious 
particulars. Tbat the star portended great events, possibly 
of an evil cbaracter, seemed evident to most writers, and 
the star of Bethlehem was frequently referred to as a 
phenomenon of a similar nature. As th.e star seen by the 
wise men foretold the birth of Christ, the new one was 
generally supposed to announce His last coming and the end 
of the world. This was already suggested by "WUhelm IV. 
in his above-mentioned letter to Peucer, and among others 
who declared their belief in this idea was the successor of 
Calvin at Geneva, Theodore Beza, who announced it in a 
short Latiu poem.-*- He even says that it is the very same 
star which was seen by the Magi ; but, as Tycho remarks, 
perhaps that was only said " poetica quadam festivitate." 
Gemma, iu his book on the comet of 1577, points out the 
great disturbances which followed the star seen by Hip- 
parchus, and expects similar ones to occur now ; Tycho 
justly remarks that it looks as if Gemma had copied all 
this from his own little book.^ Catholic authors naturally 
thought that the . star foretold the victory of their Church ; 
among these is Theodore Graminseus, Professor of Mathe- 

' Published in the above-mentioned reprint " De Nova Stella Judicia Dvorum 
Praestaotium Mathematicorum, D. Cypriani Leovitii et D. Cornelii Gemmae," 
1573, s.l. ; perhaps also elsewhere. Reprinted by Tycho, Progymn., p. 327. 

2 "De Prodigiosa Specie Naturaque Cometse . . . 1577. Per D. Cornelium 
Gemmam, Antwerp, 1578," Svo, p. 42 (compare Pcojymiuwmata, p. 565). There 
is a curious picture in this book of Belgica weeping amidst the burning ruins 
of a city, while the paternal government of Philip II. is represented by gibbets 
and wheels in the background, and the comet is blazing overhead. 

THE NEW STAR OF 1572. 69 

matics at Cologne, autlior of a book in wliicli there is 
nothing astronomical, but a great deal about old prophecies.^ 
According to one of these, dating from 1488 and founded 
on the conjunction of Jupiter and Saturn in 1484, a false 
prophet was soon to arise, who, of course, turned out to be 
Luther, and a picture is given of the prophet dressed like 
a monk, with a shrivelled little devil sitting astride on his 
neck, and followed by a small monk or choir-boy. Un- 
luckily Luther was not born in 1484, but in 1483, and 
not on the 2 2nd October, as assumed by the mathema- 
tician Cardan, who worked out his horoscope (in what spirit 
may easily be conceived), but nineteen days later. The 
above-mentioned French pamphlet of 1590, printed at a 
time when Henry IV. had not yet come to the conclusion 
that " Paris vaut bien une messe," also declares that the 
star meant the victory of the Church and the King, but 
the latter must not be a heretic, but fide plenus. The 
author also states that the star disappeared the i8th 
February 1574; "qui fut le propre iour que le feu Eoy 
Henry de Valois feist son entree en Cracouie." ^ Doubtless 
the star expired from grief at seeing this charming creature 
bury himself so far from his admiring country. Strange that 
it did not light up again with joy when he bolted from his 
Polish kingdom a few months later ! 

After this digression we shall now return to Tycho, de- 
ferring to a later chapter an account of the researches and 
speculations on the subject of the new star which he made 
in after-years, and which it would not be possible to describe 
in this place without a serious break in the continuity of 
our narrative. 

^ "Erklerung oder Auslegung eines Cometen. . . . Durch Theodorum 
Grammaeum Ruremundanura. Cdllen am Rhein, 1573, 4to." Tycho mentions 
him as "Autor Stramineus, Graminseus volebam dioere" {Prog., p. 778). 

^ This beautiful remark is also made in Gosselin's Historia Imaginwrn 
itium, Paris, 1577, 4to, p. 11. 


TRA VELS IN 1575. 

After the publication of the book on the new star Tycho 
Brahe had intended to go abroad for some time, and it appears, 
even, that he was inclined to leave his native land for ever, 
but the journey had to be put off owing to an attack of 
ague, which continued during the greater part of the summer 
of 1573. Another circumstance which doubtless contri- 
buted to keep him at home, was that he had formed an 
attachment to a young girl some months before. Her 
name was Christine, but otherwise nothing is known about 
her ; some authors say she was the daughter of a farmer on 
the Knudstrup property, others that she was a servant-girl ; 
others, again, believed her to have been the daughter of a 
clergyman. At any rate, it is certain that she was not of 
gentle blood, and this contributed greatly to estrange his 
proud relations from him, as they, of course, considered the 
connection a disgrace. Tycho had no scruples ia this 
respect, and probably considered that a quiet and domestic 
woman was more likely to be a suitable companion for him 
through life than a high-born lady to whom his scientific 
occupations, perhaps, might be distasteful. It is nowhere 
expressly stated that he and she were united by a Church 
marriage, and it is almost certain that this was not the 
case, as it is stated in several contemporary genealogies 

that Tycho was not married, but that he had children by 



an " unfree woman." i Twenty-nine years after Ms death 
Ms sister Sophia and several others of his relations signed 
a declaration stating that Tycho's children were legitimate, 
and that their mother (though his inferior in rank) had been 
his wife, adding that he would not have been allowed to 
live with an unmarried woman in Denmark for twenty-six 
years. Eut this does not in the least prove that Christine 
had been formally married to Tycho. According to the 
ancient Danish law, a woman who publicly lived with a man 
and kept his keys and ate at his table was after three 
winters to be considered as his wife. In this rule the 
Eeformation made no change, as Luther and his followers 
did not consider a Church ceremony necessary to legalise a 
marriage, but adopted the old rule of canonical law, that 
the consent of the parties made the marriage, which, there- 
fore, really dated from the betrothal {onatrimo^iium in- 
choatum), though the full consequences only began when 
the parties went to live together or were married (matri- 
monium consummatum). A natural result of these views 
was, that the parties frequently began to live together 
immediately after the betrothal, as they did not see the 
necessity of the Church ceremony, which could make no 
difference as to the legal effects of the connexion. Gradu- 
ally a change took place in these views, as the Church 
could not look with indifference at this setting aside of its 
authority; but though in Denmark betrothed people about 

^ Danslce Magazin, ii. p. 192 (Weistritz, ii. p. 70). The English traveller, 
Fynes Moryaon, tells us that Tyoho was said "to liue vnmarried, but keeping 
a Concubine, of whom he had many children, & the reason of his so lining 
was thought to be this ; because his nose hauing been cut off in a quarrell, 
when he studied in a Vniversity of Germany, he knew himselfe thereby dis- 
abled to marry any Gentlewoman of his own quality. It was also said that 
the Gentlemen lesse respected him for lining in that sort, and did not acknow- 
ledge his Bonnes for Gentlemen." Moryson heard this at Elsinore in 1593 ; 
see his " Itinerary of his ten Yeeres Travell through the twelve Domjuions of 
Germany, Bohmerland, &c." London, 1617, p. 59. 


the year 1566 began to be ptmislied if they commencecl 
living together before the ■^vedding, and an ordinance of 
1582 declares that a formal betrothal before a minister and 
witnesses shall precede a wedding, it was not yet expressly 
ordered that a Church ceremony was the only way of 
legalising a marriage, and, in fact, this was not done tiU 
a hundred years later.''^ Tycho Brahe lived just at a time 
when the law of the land was still formally unaltered, and 
it is therefore intelligible how his children might be con- 
sidered legitimate, and the companion of his life have 
been looked upon as his lawful wife. Doubtless the only 
fault anybody had to find with her was her low origin, and 
if she had been his equal in rank nobody would have thought 
that she was anything but his wife.^ 

Tycho's eldest child, a daughter of the name of Christine, 
was bom in October 1573, but died in September 1576. 
His other children were ilagdalene (bom in 15 74), 
Claudius (bom in January 1577, died six days after), 
Tyge (bom in August 1581), Jorgen (bom 1583), and 
three other daughters, Elizabeth, Sophia, and CecUy, as to 
the dates of whose birth nothing is known.* 
_ The ague seems to have left Tycho in August 1573, as 

^ By the Samke Lov of 1683 and the Church ritual of 1685. See an 
article in the Historish Tidssl~rift, fifth series, vol. L 1879, by the Danish 
ilinister of Justice, J. Xellemann. 

- Early in the sixteenth century a Danish nobleman, Mogens Lorenbalk, 
brought a young Scotch lady, Janet Craigengelt (on the female side said to 
have been related to the Grahams of Jlontrose), home to his castle, Tjele, in 
Jutland, where she lived for many years and bore him two children. Her 
son -tried in vain to obtain recognition as his father*s legitimate heir, and his 
claims were set aside chiefly because his mother had clearly not been treated 
as the mistress of the house, but rather as a dependent. On the other hand, 
the University of Wittenberg declared in favour of the legitimate birth of the 
children, evidently guided by the then ruling principle of canonical law, that 
a long intercourse with all the outer resemblance of wedlock had the same 
legal weight as a formal marriage. 

' The eldest daughter was buried in Helsingborg church. In the epitaph 
she is called Jtliol-a naturalis, which has made Langebek doubt whether she 
had the same mother as the other children (Z). Magaziv, ii. p. 194) ; but this 


we still possess a couple of observations from tlie I4tli 
of tHat montli. The lunar eclipse of the 8 th December, 
which he had computed in the book on the new star, was 
duly observed, and he was on that occasion assisted by his 
youngest sister Sophia, at that time a girl seventeen years 
of age, highly educated, and not only conversant with classi- 
cal literature, but also well acquainted with astrology and 
alchemy, and therefore in every way fit to assist her great 
brother. She was the only one of his relations who showed 
any sympathy with his pursuits, and was a frequent visitor 
in his home. In March, April, and May 1574 Tycho 
observed at Heridsvad, but the remaining part of the year 
he chiefly spent at Copenhagen, where his daughter Mag- 
dalene was born.'' In the capital his rising fame had now 
attracted considerable attention, and some young nobles 
who were studying at the University requested him to 
deliver a course of lectures on some mathematical subject 
on which there were no lectures being given at that time. 
His fiiends Dancey and Pratensis urged him to consent to 
this proposal, but Tycho was not inclined to do so, until 
the King had also requested him to gratify the wishes of 
the students, and at the same time to give the University 
a helping hand. He then yielded, and the lectures were 
commenced on the 23rd September 1574, with an oration 
on the antiquity and importance of the mathematical 
sciences. This was printed after his death, but has long 
ago become very scarce, for which reason we shall give an 
abstract of the contents.* 

very expression, which originated in the Roman jurisprudence, shows that 
the humble companion of Tycho's life was her mother (see Gibbon's Decline 
and Fall of the Soman Empire, chapter xliv,). 

' He had also observed at Copenhagen on the 24th April. Nearly all these 
observations are distance-measures of planets from fixed stars, doubtless with 
the sextant, " satis exquisite, subtracta instrument! parallaxi ; " but a small 
quadrant is also mentioned. 

'■' " Tychonis Brahei de Disoiplinis mathematicis oratio publice recitata in 


The oration begins with an .allusion to Ms having heen 
requested to lecture, not only by his friends, but also by 
the King, and then goes on to describe the various branches 
of mathematics cultivated by the ancients. Geometry has 
a higher purpose than merely measuring land, and the 
divine Plato turned aU those away from his teaching who 
were ignorant of geometry, as being unfit to devote them- 
selves to other branches of philosophy. To this he attri- 
butes the high degree of learning reached by the ancient 
philosophers, as they were imbued with geometry from their 
childhood, " while we, unfortunately, have to spend the best 
years of our youth on the study of languages and grammar, 
which those acquired in infancy without trouble." Astronomy 
is a very ancient science, and, according to Josephus, it can 
be traced back to the time of Seth, while Abraham from the 
motions of the sun, moon, and stars perceived that there 
was but one God, by whose will all was governed. It was 
next studied by the Egyptians ; while we owe our knowledge, 
above all, to Hipparchus, Ptolemy, and more recently to Nico- 
laus Copernicus, who not without reason has been called a 
second Ptolemy, and who, having by his own observations 
found both the Ptolemean and the Alphonsine theories in- 
suflBcient to explain the celestial motions, by new hypotheses 
deduced by the admirable skUl of his genius, restored the 
science to such an extent, that nobody before him had a 
more accurate knowledge of the motions of the stars. And 
though his theory was somewhat contrary to physical 
principles, it admitted nothing contrary to mathematical 
axioms, such as the ancients did in assuming the motions 

Academia Haffniensi anno 1574, et nunc primom edita . . . studio et opera 
Ounradi Aslaci Bergensis. Hafnise, 1610, 4to." Dedicated to Tycho's brother, 
Sten Brahe of Knudstrap, and the editor has added some of his own speeches. 
Second edition, Hamburg, 1621, to the title is added "in qua simul Astrologia 
defenditur et ab objectionibus dissentientium vindicatur. Cum Prseloquio 
Joach. Curtii." Both editions are very scarce. 


of tile stars in the epicycles and. eccentrics to be irregular 
witli regard to the centres of these circles, " which was 
absurd." The lecturer next alludes to the beauty of the 
celestial phenomena, and shows that we must distinguish 
between the casual contemplation of the heavens and their 
scientific examination, as only the latter will detect the 
variation in the moon's distance from us, the revolutions of 
the planets, &c. The utility of astronomy is easy to per- 
ceive, as no nation could exist without means of properly 
dividing and fixing time, while the science exalts the 
human mind from earthly and trivial things to heavenly 
ones. A special use of astronomy is, that it enables us to 
draw conclusions from the movements in the celestial regions 
as to human fate. The remainder of the lecture is devoted 
to considerations on the importance and value of astrology, 
and tries to answer the objections which philosophers and 
theologians had made against it. It is evident, from the 
detailed manner ia which this is done, how important 
Tycho considered this subject to be. We cannot, he says, 
deny the influence of the stars without disbelieving in the 
wisdom of God. The importance of the sun and moon is 
easy to perceive, but the five planets and the eighth sphere 
have also their destination, as they cannot have been 
created without a purpose, but were placed in the sky and 
given regular motions to show the wisdom and goodness 
of the Creator. The sun causes the four seasons, while 
during the increase and decrease of the moon all things 
which are analogous to it, such as the brain and marrow of 
animals, iacrease and decrease similarly. The moon also 
causes the tides, and its influence on these becomes greatest 
when that of the sun is joined to it at new-moon and 
full-moon. Sailors and cultivators of the soil have noticed 
that the rising and setting of certain stars cause stormy 
weather, and more experienced observers know that the 


configurations of tlie planets have also great influence on 
the Tveatter. Conjimctions of Mars and Venus in certain 
parts of the sky cause rain and thunder, those of Jupiter 
and Mercury storms, those of the sun and Saturn turbid 
and disagreeable air. The most ancient writers on agricul- 
ture, as well as poets and astrologers, have observed that 
the rising and setting of the more conspicuous stars 
simultaneously with the sun produced rain, wind, and other 
atmospheric changes, particularly when the planets joined 
their effect to that of the stars. ^ The sun and stars move 
in the same manner from year to year, but this is not the 
case with the planets, and the weather of one year cannot, 
therefore, be like that of another. Among planetary con- 
junctions, he mentions that of Jupiter and Saturn in 1563, 
in the beginning of the sign of Leo near the hazy stars of 
Cancer (Prsesepe), which Ptolemy already considered pesti- 
lential. This conjunction was in a few years followed by 
an outbreak of the plague. While many people admitted 
the influence of the stars on nature, they denied it where 
mankind were concerned. But man is made from the 
elements, and absorbs them just as much as food and drink, 
from which it follows that man must also, like the elements, 
be subject to the influence of the planets ; and there is, 
besides, a great analogy between the parts of the human 
body and the seven planets. The heart, being the seat of 
the breath of life, corresponds to the sun, and the brain to 
the moon. As the heart and brain are the most important 
parts of the body, so the sun and moon are the most power- 
ful celestial bodies ; and as there is much reciprocal action 
between the former, so is there much mutual dependence 
between the latter. In the same way the liver corresponds 

1 " Habent se enim stellse fixse in coelo veluti matres, quae nisi a septem 
errantibus stellis stimulentur et impregnentar, steriles sunt et nihil in fiao 
inferiori natura progignunt " (Oratio, p. 20). 


to Jupiter, tlie kidneys to Venus, tlie milt to Saturn, the 
gall to Mars, and the lungs to Mercury, and the resem- 
blance of the functions of these various organs to the 
assumed astrological character of the planets is pointed out 
in a manner similar to that followed by other astrological 
writers. He believes experience to have shown that those 
who are born when the moon is affected by the evil planets 
(Saturn and Mars) and is unluckily placed, have a weak 
brain and are under the influence of passions, while those 
in whose case the sun was inflQenced by those planets 
suffered from palpitation of the heart. But if both lumi- 
naries are in .unlucky aspects, those born at that time are of 
weak health and intellect. Those people at whose birth 
Saturn, the highest planet, was favourable, are inclined to 
sublime studies, while those whom Jupiter has influenced 
are attracted to politics. The solar influence makes people 
desire honour, dignities, and power; that of Venus makes 
them devote themselves to love, pleasures, and music ; while 
Mercury encourages people to mercantile pursuits, and the 
moon to travelling. 

Many philosophers and theologians, continued Tycho in 
his lecture, have contended that astrology was not to be 
counted among the sciences, because the moment of birth 
was diflacult to fix, because many are born at the same 
moment whose fates differ vastly, because twins often meet 
with very different fortunes, while many die simultaneously 
in war or pestilence whose horoscopes by no means foretold 
such a fate. It had also been maintained that a knowledge 
of the future was useless or undesirable, and theologians 
added that the art was forbidden in God's Word and drew 
men away from God. To these objections Tycho answered, 
that even if there was an error of an hour in the assumed 
time of birth, it would be possible from subsequent events to 
calculate it accurately. With regard to war or pestilence, 


prudent astrologers always made a reservation as to pubKc 
calamities whicli proceed from universal causes. Difference 
of education, mode of life, and similar circumstances ex- 
plained the different fates wliicli people bom at the same 
time met with ; and as to twins, they were not born exactly 
at the same moment, and one was always naturally 
weaker than the other, and this the stars could not correct. 
Astrology was not forbidden in the Bible, but sorcery 

So far Tycho's astrological ideas are in accordance with 
those of contemporary and previous writers on such sub- 
jects, but towards the end of his discourse he shows more 
distructly than most of these, that he did not consider the 
fate of man to be absolutely settled by the aspect of the 
stars, but that God could alter it as He willed. Nor was 
man altogether bound by the influence of the stars, but God 
had so made him that he might conquer that influence, as 
there was something in man superior to it. The objection 
to astrology, that it was a useless art, as knowledge of the 
future was undesirable, would only hold good if it were 
impossible to resist the influence of the stars; but being 
forewarned, we might try to avert the threatening evils, and 
in this way astrology was of great use. 

In conclusion, Tycho stated that as the doctrine of the 
prunum mobile (spherical astronomy) was very easy, and 
was frequently lectured on in. the University, he had thought 
it more advisable to take for his subject the motions of 
secundum indbile, explain the method of calculatiug the 
motions of the seven planets by the Prutenic tables, which 
were the most accurate ones, and describe the circles by 
means of which the tables had been computed. 

Early in 1575 these lectures were finished, and Tycho 
Brahe shortly afterwards started on the long-deferred 

TRAVELS IN 1575. 79 

journey.^ Leaving his family at home imtil lie had decided 
where he would finally settle down, he went first to Cassel 
to make the acquaintance of the distinguished astronomer, 
Landgraye Wilhelm IV. of Hesse. Wilhelm was horn in 
1532, and was the son of Landgrave Philip the Magnani- 
mous, one of the most determined champions of the Eefor- 
mation, who, after the disastrous battle of Mlihlberg (1547), 
had surrendered to the Emperor, and had been kept a close 
prisoner for five years, during which anxious time his 
dominions had been governed by Wilhelm. When Philip 
became free in 1552, Wilhelm gladly turned back to the 
learned occupations, to which he had already for some years 
been devoted. By accident he came across the curious work 
of Peter Apianus, Astronomicum Ccesareum, in which the 
orbits of the planets are represented by movable circles of 
cardboard, and he became so much interested in the subject, 
that he had circles of copper made for the same purpose. 
Having afterwards studied Purbach's planetary theory and 
the other principal works of the time, he became, like Tycho, 
convinced of the necessity of making systematic observations, 
as he found considerable errors in the existing star cata- 
logues. In 1 561 he built a tower on the Zwehrer Thor at 
Cassel, of which the top could be turned round to any part 
of the sky, and here he observed regularly up to 1 5 6'J, when 
the death of his father and his own consequent accession to 
the government of his dominions gave him less leisure for 
scientific occupations. As yet he had not any astronomer 

' Shortly before starting he had occasion to show his friendship for his 
former tutor Vedel and his patriotism. Vedel was just in the act of finishinij 
his translation of the Danish Chronicle of Saxo Grammaticus (from the end 
of the twelfth century), but the cost of the paper necessary for so large a work 
was so great, that Vedel's friends feared that the work might remain un- 
printed. Tycho wrote a Latin poem to encourage his friend, calling on the 
Danish women to sacrifice some of their linen, and to send it to the paper- 
mill in Scania, lest the deeds of their ancestors should be buried in oblivion 
(Wegener's Life of Yedel, p. 83). 


to assist liim, and the work at his observatory had for a 
long time made little or no progress, when Tycho Brahe 
arrived at Cassel in the beginning of April 1575. The 
Landgrave was well pleased to receive the young astronomer 
as his guest, and they conversed by day about their favourite 
science, and observed the heavens by night together, the 
Landgrave with his own quadrants and unwieldy torqueta, 
Tycho with some portable instruments, among which was 
probably his sextant. Among other observations they deter- 
mined the position of Spica Virginis.'' Naturally they dis- 
cussed the nature and position of the new star, and the 
Landgrave told Tycho how he had once been so intent on 
determining the greatest altittde of the star, that he had 
not even desisted when he was told that part of the house 
was on fire, but had calmly finished the observation before 
leaving the observatory. Tyclio was also interested to learn 
that the Landgrave had remarked how the motion of the sun 
became retarded when it approached the horizon at sunset, 
which miglit be seen by watching a sun-dial. Tycho recol- 
lected having read the same in the observations of Bernhard 
Walther (before whom, however, Alhazen had recognised in 
this phenomenon an effect of refraction), and he determined 
to follow up the matter by-and-by, so as to be able to cor- 
rect observations made at low altitudes for refraction.^ 

More than a week had elapsed in thus exchanging ideas 
and opinions, when a little daughter of the Landgrave died, 
and Tycho, who did not wish to intrude his company on the 

1 Tychonis JEpUt. Astron., Dedication. In his Progymn., p. 616, Tycho 
states that the Landgrave on this occasion gave him a copy of his own cata- 
logue of improved star-places. Tycho prints as specimens the places of Alde- 
baran, Betelgeux, and Sirius ; but though superior to the positions given by 
Alphonsus and Copernicus, those of the Landgrave were as yet very inferior 
to Tycho's. We shall, farther on, see how the observations made at Cassel 
afterwards became much more accurate than they were at the time of Tycho's 

' Gassendi, p. 29. 

TRAVELS IN 1575. 81 

afflicted father, took his departure. He never saw the Land- 
grave again, but the visit of the young enthusiast had re- 
newed the wavering scientific ardour of his host, and the 
friendship thus commenced was revived in after-years 
by frequent correspondence and the interchange of obser- 

Prom Oassel, Tycho went to Frankfurt -on- the -Main, 
where he purchased some books at the half-yearly mart, 
particularly some of the numerous pamphlets on the new 
star. He went thence to Basle, where he had already spent 
some time in the winter of 1568—69, and where he now 
found his stay so agreeable that he thought seriously of 
settling down there. The University of Basle was one of 
the most important centres of learning in Europe, and Tycho 
might hope to find the same refined tastes and culture 
among the scientific men living there which, some sixty 
years before, had decided Erasmus to take up his residence 
at Basle. The central situation of the city, between Ger- 
many and France and not far from Italy, seemed also very 
convenient.'"' Deferring, however, for the present the final 
step of returning home for his family, Tycho went through 
Switzerland to Venice, and spent some days there, after 
which he retraced his steps back to Germany, and went in 
the first instance to Augsburg. The friendships with the 
brothers Hainzel and Hieronimus Wolf formed during his 
former visit had in the meantime not been forgotten, and 
several letters had been exchanged between them. Thus, 
Paul Hainzel had in March 1574 written to express his 
warmest thanks for a copy of Tycho's book on the new star, 
and in March 1575 both he and Wolf had written to tell 
Tycho that they had succeeded in procuring for him from 
Schreckenfuchs of Ereiburg a zodiacal sphere constructed 
according to the description of Ptolemy as formulated by 

' Attr. Inst. Mechanica, fol. G. 2. 


Copernicus.^ The money sent by Tyclio had been stolen by 
the carrier, who had never since been heard of, but the 
instrument had now arrived, and would be forwarded.^ Tycho 
can hardly have received these letters before starting from 
home, and was therefore possibly still ignorant of another 
piece of news contained in them, namely, that the great 
quadrant at Goggingen, which he had designed six years 
before, had in the previous December been blown down and 
destroyed in a great storm. ^ The great globe which he had 
ordered to be made during his former visit was now nearly 
completed, and was the following year brought to Denmark 
with great trouble. At Augsburg, Tycho on this occasion 
made the acquaintance of a painter, Tobias Gemperlin, and 
induced him to go to Denmark, where he afterwards painted 
a number of pictures for Uraniborg and the royal castles. 

At Eatisbon great numbers of princes and nobles from 
all parts of the empire were just then gathering to witness 
the coronation as King of the Eomans of Rudolph the Second, 
King of Hungary and Bohemia, on the 1st November. 
Tycho also betook himself thither in the hope of meeting 
the Landgrave, and perhaps some other scientific men. He 
was, however, disappointed as to the Landgrave, who did 
not appear ; but he had the consolation of meeting, among 
others, the physician-in-ordinary to the Emperor, Thaddaeus 
Hagecius or Hayek, a Bohemian, whose name we have 
already met with among the writers on the new star. He gave 

^ Erasmus Oswald Schreokenfuchs (1511-1579), Professor of Mathematics, 
Khetorics, and Hebrew, first at Tubingen, afterwards at Freiburg in Breisgau ; 
editor of the works of Ptolemy (Basle, 1551), and author of commentaries on 
the writings of Sacrobosco, Purbach, and Regiomontanus. 

' By Petrus Aurifaber, "cum supellectile sua" (Was he the maker of the 
globe?) These letters are published in T. Brake et ad eum doct. vir. Epist., 
pp. II seq. Whether Tycho ever got the sphere is not known. 

^ It may have been re-erected later, as Job. Major wrote to Tycho Brahe in 
1577 that it was still in use ; but, on the other hand, P. Hainzel wrote in 1579 
that he had not observed the comet of 1577 for want of convenient instru- 
ments [T. B. et doct. vir. Epist., pp. 42 and 46). 

TRAVELS IN 1575. 83 

Tycho a copy of a letter he had received from Hieronimus 
MurLOsius of Valencia on this subject, and Tycho tried in 
vain to dissuade him from publishing an answer to the 
scurrilous and absurd assertions of Eaimundus of Verona.^ 
Another and most precious gift which Hagecius bestowed 
on Tycho on this occasion was a copy of a MS. by Coperni- 
cus, De Hypothesibus Motuum Ccelestium Commentariolus, an 
account of the new system of the world, which its author 
had written for circulation among friends some ten years 
before the publication of his book, De Eevolutionihus, but 
which had never been printed.^ In after years Tycho 
communicated copies of this literary relic to various 
German astronomers. Probably he presented to Hagecius 
in return a copy of his own paper on the star, as the latter 
is quoted in Hagecius' reply to Eaimundus.^ 

From Eatisbon Tycho returned home vi§, Saalfeld and 
Wittenberg. At the former place he visited Erasmus Eein- 
hold, the younger, a son of the author of the " Prutenic 
Tables," who showed him his father's manuscripts, among 
which were extended tables of the equations of centre of 
the planets for every lo' of the anomaly.* At Wittenberg 
he inspected the wooden triquetrum with which Wolfgang 

^ Progymn., pp. 567 and 734; see also above, p. 64. 

^ Progymn., p. 479. Though the description there given of the MS. ought 
to have attracted attention, and have led to a search for copies of it, the Com- 
mentariolus vexx^dXw^di perfectly unknown till the year 1878, when it was noticed 
that there was a copy of it in the Hof-Bibliothek at Vienna, and immediately 
afterwards another copy was found at the Stockholm Observatory. The 
Vienna MS. had been presented by Longomontanus on his departure from 
Prague in 1600 to another of Tycho Brahe's disciples, Joh. Eriksen, and it is 
therefore doubtless a copy of the MS. belonging to Tycho. See Prowe, 
Aicolaus Ooppcrnicus, i. part ii. p. 286. 

' Sanske Magaein, ii. p. 196, quotes Thomasini ]llog. Viror. Illustr., 
according to which, Tycho, in his younger days, received an offer of an 
appointment at the Emperor's court. There is no confirmation anywhere of 
this statement ; but if the offer was ever made, it was probably done at E,atis- 
bon in 1575. 
' Progymn., p. 699. 


Scliuler and Johannes Praetorius had observed the new- 

About the end of the year Tycho returned borne, appa- 
rently intending very soon to leave his native land for ever 
in order to reside at Basle. He bad, however, not yet con- 
fided his intentions to anybody, but luckily King Frederick 
II. bad his attention specially drawn to Tycho through an 
embassy to Landgrave Wilhelm, which happened to return 
to Denmark from Cassel about that time. The Landgrave 
had requested the members of the embassy to urge the king 
to do something for Tycho, so as to enable him to devote 
himself to his astronomical studies at home ; as these would 
do much credit to his king and country, and be of great 
value for the advancement of science.^ When Tycho paid 
his respects to the king, the latter offered him various 
castles for a residence, but Tycho declined these offers. 
King Frederick was, however, fond of learning, and anxious 
to retain in the kingdom so promising a man; and he 
shortly afterwards sent off a messenger with orders to 
travel day and night, until he could deliver into Tycho's 
own hands the letter of which he was the bearer. On the 
I ith of February, early in the morning, as Tycho was 
lying in bed at Knudstrup, turning over in his mind his 
plan of emigrating, the royal messenger, a youth of noble 
family and a connection of Tycho's, was announced, and 
was at once brought to his bedside to deliver the king's 
letter. In this Tycho was commanded immediately to come 
over to Seeland to wait on the king. He started the same 
day, and arrived in the evening at the king's hunting-lodge 
at Ibstrup, near Copenhagen.' The king now told him that 

^ Progymn., p. 636; see also above, p. 58. 

^ Epist. Astron., Dedication, fol. 2. 

' Afterwards called Jaegersborg, about five English miles north of Copen- 
hagen ; it was demolished long ago. The present king's summer residence, 
Berustorff, is close to the place. 

TRAVELS IN 1575. 85 

one of his courtiers had understood from Tycho's uncle, Sten 
Bille, that Tycho was thinking of returning to Germany, 
and asked him whether he had perhaps refused to accept a 
royal castle because he feared to be disturbed in his studies 
by affairs of court and state. The king next told him how 
he had lately been at Elsinore, where he was building the 
castle of Kronborg, and that his eye had fallen on the little 
island of Hveen, situated in the Sound, between Elsinore 
and Landskrona in Scania, and that it had occurred to him 
that this lonely little spot, which had not been granted in 
fee to any nobleman, might be a suitable residence for the 
astronomer, where he might live perfectly undisturbed ; 
adding, that he believed he had heard from Sten Bille 
before Tycho went to Germany that he liked the situation. 
The king offered him the island and promised to supply him 
with means to build a house there. He finally told Tycho 
to think the matter over for a few days, and give his final 
answer at the castle of Frederiksborg ; if he accepted the 
offer, the king would immediately give the necessary orders 
for payment of a sum of money for the building. 

Having returned home, Tycho at once wrote a long 
letter to his friend Pratensis, telling him in detail all that 
had happened, and confessing his former intention 'of 
leaving Denmark. He asked Pratensis to show the letter 
only to Dancey, and requested them both to advise him in 
the matter.-"- They both strongly urged him to accept the 
king's offer, which he accordingly did, and already on the 
1 8th of February the king by letter granted Tycho "five 
hundred good old daler " annually until further orders.^ 

' T. B. et Doct. Vir. Epist., p. 2i et seq. In the letter of February 14, 
Tycho asks Pratensis to tear up or burn the letter as soon as Dancey had seen 
it, and in his reply next day, Pratensis writes that he had destroyed it. Tyoho 
must therefore have kept a copy. 

^ About ;^II4, but of course this represented at that time a much greater 
sum. In Denmark the first Joachimsthaler had been coined in 1523, exactly 
of the same value as those first issued in North Germany in 15 19, which value 


Pour days after, on the 2 2iid February 1576, Tycto paid 
his first visit (at least as far as we know) to the little 
island which was destined to become famous through him, 
and the same evening took his first observation there of a 
conjunction of Mars and the moon.'^ If he could have 
foreseen that he was destined to furnish the means of cir- 
cumventing the tricks of the inobservable Sidus (as Pliny 
called Mars), and himself to add more to our knowledge of 
the moon's motion than any one had done since Ptolemy, 
he would certainly by this coincidence have been confirmed 
in his belief in astrology. On the 23 rd May a document 
was signed by the king of which the following is an exact 
translation : ^ — 

" We, Frederick the Second, &c., make known to all men, 
that we of our special favour and grace have conferred and 
granted in fee, and now by this our open letter confer and 
grant in fee, to our beloved Tyge Brahe, Otte's son, of 
Knudstrup, our man and servant, our land of Hveen, with 
all our and the crown's tenants and servants who thereon 
live, with all rent and duty which comes from that, and is 

the Danish daler retained nearly unaltered, though the name changed, first 
to species (from in specie, or in one piece), then to rigsdaler species. The 
coinage had greatly deteriorated during the war with Sweden, hence doubtless 
the expression " good old daler." 

^ ITebruarii die 22. Existente in M. C ultima in capite Hydrse quae est 
versus ortum, et sola juxta coUum, apparebat visibilis conjunotio 5 et (J ad- 
modum partilis, adeo ut 5 inferiore et meridionaliore cornu fere attingeret 
corpus (J distans saltern ab eo parte sexta sui diametri acoipiendo distantiam 
hano ab inferior! cornu limbi. Erat autem circa idem teinpus per observa- 
tionem alt. luoidiss. in pede Orionis 11 g. 20 m. — H. 9 M. 30. Infimus vero J 
limbus circa quern $ conspiciebatur elevari visus est lo g. 50 m. Observatio 
hffio facta i. Huennae. Langebek in Danske Mag., ii. p. 194 (Weistritz, ii. p. 
73), refers to this visit to Hveen as made in the year 1574. In the original 
the year is not given, and the observation follows after one of May 19, 1574. 
But on February 22, 1574, the moon was only a few days old, and Mars was 
at the other side of the heavens, while they were very close together on the 
same date in 1576. 

2 DansJce Magazin, ii. p. 198. 

TRAVELS IN 1575. 87 

given to us and to the crown, to have, enjoy, use and bold, 
quit and free, without any rent, all the days of his life, and 
as long as he lives and likes to continue and follow his 
studia matheniatices, but so that he shall keep the tenants 
who live there under law and right, and injure none of them 
against the law or by any new impost or other unusual tax, 
and in a,ll ways be faithful to us and the kingdom, and 
attend to our welfare in every way and guard against 
and prevent danger and injury to the kingdom. Actum 
Trederiksborg the 23rd day of May, anno 1576. 

" Feedeeick." 

The same day the chief of the exchequer, Christopher 
Valkendorf, was instructed to pay to Tycho Brahe 400 
daler towards building a house on the island of Hveen, for 
which Tycho was himself to provide building materials. 
This money was paid on the 27th May.'' Just at the 
moment when everything was settled and Tycho's prospects 
in life were most brilliant, he had the grief to lose his 
friend Johannes Pratensis, who died suddenly on the 1st 
June from a bleeding of the lungs while lecturing in the 
University. He was only thirty-three years of age, and 
had been professor of medicine since i 5 7 1 . Tycho had 
promised to write a Latin epitaph over his friend in case 
he should survive him, and he had it printed in 1584 at 
his own printing office at Uraniborg. He also caused a 
monument to be erected to the memory of Pratensis in the 
Cathedral of Copenhagen.^ 

' !Friis, Tyge Brahe, p. 58. 

' The epitaph is reprinted in Danslce Magazvn, p. 199 (Weistritz, ii. 84), and 
in T. B. et ad eum Boot. Vir. Epist., p. 28, 



In tte beautiful scenery along tte coast of the Sound 
between Oopenbagen and Elsinore, the isle of Hveen with 
its white cliffs, rising steeply out of the sea, forms a very 
conspicuous feature. It is about fourteen English miles 
north of Copenhagen, and about nine miles south of Elsi- 
nore, rather nearer to the coast of Scania than to that of 
Seeland. The surface is a nearly flat tableland of about 
two thousand acres, sloping slightly towards the east, and of 
an irregularly oblong outline, the longest diameter extending 
from north-west to south-east and being about three miles 
long. From time immemorial it was considered an append- 
age to Seeland, but in 1634 it was placed under the jurisdic- 
tion of the court of justice at Lund in Scania, because the 
inhabitants had complained of the long distance to their 
former court of appeal in Seeland.''- In consequence of 
this change the island was ceded to Sweden in 1658, when 
the Danish provinces east of the Sound were conquered by 
the king of Sweden. Though there are no considerable 
woods on the island and the surface is but slightly un- 
dulatedj the almost constant view of the sea in all directions, 
studded with ships and bounded by the well- wooded coasts 

^ There is still extant a Latin poem written by T. Brahe in 1592, "In 
itinere a Hingstadio donium," in ■which he charges the judge who had tried 
some lawsuit of his with injustice. DansJce Magazin, ii. p. 279. About the 
change of jurisdiction see Bang's Samlinger, ii. p. 265 (Weistritz, ii. p. 226, 
and i. p. 56). 


of Seeland aud Scania in the distance, helps to form very 
attractive scenery, wliich adds to the peculiar charm the 
island has for any one who is interested in the great 
memories connected with it. One can understand why 
Tycho calls it " Insula Venusia, vulgo Hvenna," as if it 
were worthy of being called after the goddess of beauty. 
Another name, which Tycho mentions as sometimes applied 
to the island by foreigners, is " Insula Scarlatina," and 
with this name a curious and probably apocryphal story 
is connected, which is told by the English traveller, Fynes 
Moryson (who was in Denmark in 1593), in the following 
words : " The Danes think this Hand of Wheen to be of 
such importance, as they have an idle fable, that a King of 
England should offer for the possession of. it, as much 
scarlet cloth as would cover the same, with a Eose -noble 
at the comer of each cloth. Others tell a fable of like 
credit, that it was once sold to a Merchant, whom they 
scoffed when he came to take possession, bidding him take 
away the earth he had bought." ^ 

The island forms one parish, and the church, which is 
the only building to be seen with the naked eye from the 
Danish coast, is situated at the north-west corner of the 
island, close to the edge of the cliff. As already men- 
tioned, the island is a table-land, with steep cliffs round 
nearly the whole circumference, through which narrow glens 
in several places form the beds of small rivulets, the pret- 
tiest one being Bakvik, on the south-east coast. At the 
time of Tycho Brahe the inhabitants lived in a village 
called Tuna {i.e., town, Scottice, "the toun"), towards the 
north coast; there were about forty farms, and the land 
was tilled in common. From the map in Blaev's Grand 

1 An Itinerary written by Fynes Moryson, &c., London, 1617, fol., p. 60. 
The story also occurs in P.D. Huetii Oommentarius de Rebus ad eum pertineiiti- 
bus, Amsterdam, 1 7 1 8, 8vo, p. 85 . Tyeho merely mentions the name Scarlatina, 
Astr. Inst. Meek, fol. G. 2, and De Mundi Aeth. Sec. Phaen. ii. Preface. 



Alias it appears that most of the land in the south- oasteni 
half of the island was only used for grazing. "We give here 
a reduced copy of Blaev's map, which agrees well with 

IIVEEN AT THE Time ()!■' Tyoho Buaue. 

A. Uraniborg. 

E. Stjernoborg Observatory. 

C. Farm. 

D. Workshop. 

E. ■Windmill. 
P. Village 
G. Pai)er-mill. 


II. Cliuroli. 

1. Hill where Potty Sessions were hoW. 

K, L, M. l''i.sli-iiiiiiils. 

N. (irove of nut-trooH. 

0. MoraHU with uldor ti-uus. 

P, Q, K, S. lluins of old forU. 

T. A small wood. 

Tycho's own map,i except that we have slightly altered the 
contour of the island, in accordance with modern maps. 

^ Astr, Init, Mechanica, fol. I. 2, and Eplat. Aslron,, p. 264. There is a 
small copy of it on the frontispiece of Kupler's Tubulai Jiiiilnlp/unri;. 

' I possess another larf^'o map (18 in. liy 13 in.), with ime pago letterpress 
on the back, "Topographia Insulas lIuun£B in Celebri Porthmo Kcgni Dunias 


Neither before Tycho's time nor afterwards has this 
little island played any part ia the history of Denmark, 
and yet tradition points to a time long ago when even this 
little spot is supposed to have been the scene of heroic 
deeds. On the map appear the ruins of four castles or 
forts, which are supposed to have been destroyed in 1288, 
when the Norwegian king, Erik the Priesthater, ravaged 
the coasts of the Sound. Nowadays a few stones and a 
slight rise of the ground scarcely marks the site of each 
fort, but in Tycho's time there were more distinct traces of 
them left.'' Their names were Nordborg, on the north 
coast; Sonderborg, on the south-west coast; Hammer, at 
the north-east, and Carlshoga, at the south-east corner. 
Tycho's friend and former tutor, Vedel, published a collec- 
lection of ancient Danish popular ballads and romances, 

quern vulgo Oersunt uocant. Effigiata Colonise, 1586." I believe it belongs 
to Braunii Theatrum Urhium. There are very few details on it, and the 
coast-line is very incorrect, but the plans and views of TJraniborg in the 
corners of the map, and the descriptive letterpress on the back, are of value, 
as they contain some particulars not to be found elsewhere, and the author 
has evidently got reliable information, probably from A. S. Vedel, who is 
known to have contributed to the work. Willem Janszoon Blaev {1571- 
1638) had himself lived at Hveen with Tycho. The following particulars from 
the description of the island in his son's Grand Atlas, ou Cosmographie Blaviane 
(Amsterdam, 1663, vol. i. p. 61), are of interest : — "EUe est fertile en bons 
fruits et n'a aucune partie qui soit sterile, elle abonde en toutes sortes de gros 
bestail, nourrit des daims, lievres, lapins et perdrix en quantity. La pesohe y 
est de tons costez : elle a un petit bois de couldriers, noisettiers, dont jamais 
les noix ne sont mangles des vers ny vermolues. II ne s'y trouve aucun loir 
ny taulpe. . , . Oette isle n'a point de riviere, mais quantity des ruisseaux et 
fontaines d'eau douce. Vne entre autres qui ne gele jamais, ce qui est tres- 
rare en ces quartiers." A similar account is given in Wolf's Eneomion Rerjni 
Danice, Copenhagen, 1654, p. 525. 

' The Swedish antiquarian, Sjoborg, who visited the island in 18 14, men- 
tions a place close north of the south-east ruin, called Lady Grimhild's grave, 
of which he could find no trace. On the north-east coast there was another 
ruin, apparently a quadrangular building, 80 feet by 24, with a walled-in 
enclosure in front. It was called the Monks' Kirk, but nothing is known 
about it, and it is not mentioned by Tycho. See Sjoborg, Samlingar for 
Nordens Forniilskare, T. iii., Stockholm, 1830, pp. 71-82. About the four 
castles see also Braun's map, where it is stated that there were (iu 1586) no 
ruins left, but only traces of the foundations. 


among wHcli are three whicli give the following account 
of the traditions about these ruins.'' 

Lady Grimhild, who owned the whole island, made a 
1 festival at Nordborg, to which she, among others, invited 
her brothers, Helled Haagen and Folker, the minstrel, both 
well-known figures in Danish medieeval ballads. She in- 
tended, however, to slay the two brothers, with whom she 
was at enmity, but they accepted her invitation, though 
they were warned while crossing the Sound, first by a 
mermaid and next by the ferryman, both of whom were 
beheaded by Helled Haagen as a punishment for the evil 
omen. On arriving at Nordborg they were well received 
by Grimhild, who, however, soon persuaded her men to 
challenge the brothers to mortal combat. She was specially 
infuriated against Helled Haagen, and enticed him into 
promising that he would confess himself defeated if he 
should merely stumble. To bring about this result, she 
had the lists covered with hides, on which peas were strewn, 
and of course Helled Haagen slipped on these, and, true 
to his vow, remained lying and was slain. His brother, 
Folker, was likewise killed. But one of Grimhild's maids, 
Hvenild, after whom the island got its name, bore a son 
who was called Kanke, and who afterwards avenged the 
death of his father Helled Haagen. The poems merely 
mention the revenge, without going into details, but in his 
introduction Vedel tells how Ranke enticed Grimhild into a 
place in Hammer Castle, where he said his grandfather, 
Niflung or Niding, had hidden his treasure, but when she 
had gone inside, he ran out and bolted the door, leaving 
her to die of hunger. The resemblance of this story to 
the principal events of the Niebelungenlied is striking, 
and doubtless the story is, both in the German epic and 

^ I take the following account from the Danish poet Heiberg's delightful 
article on Hveen and its state in 1S45, in his year-book, Urania, for 1846. 


in tie Scandinavian tradition, derived from a common 

Nearly in the centre of tie island, 1 60 feet above tie 
level of tie sea,^ Tycio selected a site for iis new residence 
and observatory, wiici ie very appropriately called Urani- 
burgum or Uraniborg, as it was to be devoted to tie study 
of tie ieavens. Tie work was at once commenced, and 
on tie 8ti August 1576 tie foundation-stone was laid. 
Tie Frenci minister Dancey iad asked to be allowed to 
perform tiis ceremony, and iad provided a iandsome stone 
of porpiyry witi a Latin inscription, stating tiat tie 
iouse was to be devoted to piilosopiy, and especially to 
tie contemplation of tie stars. Some friends and otier 
men of rank or learning assembled early in tie morning, 
" wien tie sun was rising togetier witi Jupiter near 
Eegulus, wiile tie moon in Aquarius was setting ; liba- 
tions were solemnly made witi various wines, success was 
wisied to tie undertaking, and tie stone was put in its 
place at the souti-east corner of tie iouse at tie level of 
tie ground." ^ Tie building operations were now steadily 
proceeded witi im.der tie direction of tie arciitect, Hans 
van Stenwinciel from Emden, but Tycio doubtless super- 
intended tie work iimself, as ie seems to have almost 
constantly resided in tie island. We find, at least, tiat 

^ According to another tradition mentioned by Sjoborg {I. c, p. 74), Eanke 
threw the keys of Hammer Castle into the sea, and bewitched the castle so 
that it sank into the earth or into the sea ; but if there shall ever be three 
posthumous men in the island at the same time, each called after his father, 
then Hammer Castle shall again stand in its old place, and the keys be found. 
Other traditions say that Hvenild was a giantess (Jettekvinde), who carried 
pieces of Seeland in her apron over to Scania, where they formed the hills of 
Runeberga, but as her apron-strings burst on the way, she dropped a piece in 
the sea, which formed the island of Hveen. The hill close to Uraniborc, 
Hellehog, where in Tycho's time the local court was held, is evidently called 
after Helled Haagen. 

2 According to Picard 27 toises {Ouvrages de Mathematique, p. 71). 

^ Astron, Inst. Mechanica, fol. H. 6. 


lie took observations pretty regularly from December 1576. 
On Hs birthday, tlie 14th December, lie commenced a 
seiies of observations of the sun, wiiicli were steadily con- 
tinued for more than twenty years.^ Having now plenty 
of occupation, Tycho thought it best to decline an offer 
made to him the following year by the professors of the 
University, who on the i8th May 1577 unanimously paid 
him the compliment of electing him Rector of the Uni- 
versity for the ensuing year, although it had not, since the 
Reformation, been customary to elect anybody to this post 
who was not a professor. Tycho replied on the 2 1 st May, 
expressing his appreciation of the proffered honour and his 
regrets that the building operations and other business 
obliged him to decline the post offered him.^ 

Although the house was probably soon sufficiently ad- 
vanced to enable Tycho to take up his residence in it, it 
does not appear to have been completed tUl the year 1580. 
Uraniborg was situated in the centre of a square enclosure, 
of which the comers pointed to the four points of the com- 
pass. The enclosure was formed by earthen walls, of which 
the sides were covered with stones, about 1 8 feet high, 1 6 
feet thick at the base, and 248 feet from comer to corner.^ 
At the middle of each wall was a semicircular bend, 7 3 feet 
in diameter, and each enclosing an arbour.* At the east 

^ "Die 14 qui milii est natalis feci primam observationera Hvenae ad Solem 
circa ipsum Solstitium hybemum et inveni alt. © meridianam miniEnam quae 
illic potest 10° 43'." Previous to this date there is only an observation of Mars 
on the 22nd October. 

^ Tycho's answer is printed in Sanske Magazin, ii. p. 202, see also Kordam, 
Kjohenhavm Universitets Historie, Ci)penhagen, 1872, vol. ii. p. 174. 

^ Here and in the following, English measures are always used, Tycho 
expresses all his measures in feet, of which one is = 0.765 Trench foot = 0.815 
English foot, or in cubits of 16.1 English inches. See D'Arrest's paper on the 
ruins of Uraniborg in Astron. Naehrichten, No. 1718. 

* On the figure on Braun's map (see above, p. go note) the four walls are 
perfectlyatraight, and the four arbours are in the middle of the flower-gardens. 
The semicircular bends were therefore later improvements. 



and west angles gates gave access to the interior of the 
enclosure, and in small rooms over the gateways English 
mastiffs were kept, in order that they might announce the 
arrival of strangers by their barking. At the south and 
north angles were small buildings in the same style as the 
main edifice, and affording room respectively for the printing 

XJeanieoeg and Grounds. 

office and for the domestics. Under the latter building was 
the castle-prison, probably used for refractory tenants.^ In- 
side the walls were first orchards with about three hundred 
trees, and inside these, separated from them by a wooden 

^ See letterpress on Braun's map. This cellar is one o£ the very few rem- 
nants now left of Tyoho's buildings. 


paling, flower-gardens. Four roads ran through the orchards 
and gardens from the four angles of the enclosure to the 
open circular space in the middle, where the principal build- 
ing was situated on a slightly higher level than the sur- 
rounding grounds. Uraniborg was built (apparently of red 
bricks with sandstone ornaments) in the Gothic Eenaissance 
style, which towards the end of the sixteenth century was 
becoming more generally adopted in the North of Europe, 
where the heavier mediaeval style had hitherto still been 
the ruling one, so that Tycho Brahe's residence became 
epoch-making in the history of Scandinavian architecture. 
The slender spires and tastefully decorated gables and 
cornices were indeed in better harmony with the peaceful 
and harmonious life of a student of the heavens than the 
more severe and dry Gothic style which the Renaissance was 
superseding ; and the pictures, inscriptions, and ornaments 
of various kinds profusely scattered through the interior 
reminded the visitor at every step of the pursuits and tastes 
of the owner. 

The woodcut below (which, like the previous and follow- 
ing ones, is a reduced copy of a figure in Tycho's own 
description) gives a general idea of the aspect of the edifice 
from the east, and by comparison with the plan of the 
ground-floor on the next page, the reader will get a clear 
idea of this remarkable structure.^ The base of the 
principal and central part was a square, of which each side 
was 49 feet long, and to the north and south sides of this 
there were round towers i8 feet in diameter, surrounded 
by lower outhouses for fuel, &c., while narrow towers on the 
east and west sides contained the entrances. Including the 
towers, the entire length of the building from north to south 

^ The buildings and instruments are described in Epist. Astron,, p. 21S cJ 
seq., and Astron. Inst. Mech., fol. H. 4 et scq. Some short Latin inscriptions, 
with which various places in the house were ornamented, are given in Resenii 
Inscriptiones Hafnienses (1668), p. 334, reprinted in Weistritz, i. p. 225. 



was about i oo feet. The central part was surmounted by 
an octagonal pavilion, with a dome with clock-dials east and 
west, and a spire with a gilt vane in the shape of a Pegasus. 
In the pavilion there was an octagonal room with a dial in 
the ceiLing, showing both the time and the direction of the 
wind, and round the pavilion ran an octagonal gallery, north 
and south of which were two smaller domes with allegorical 


I\5VL-\ PcSTHMi D/sari 

^ ^eaa nrta cnnuEi iCSo 


HV^NNA Astronomlfl mJiouTon- 
a TtmoMK B a A HS 

Urasibokg from the F.ast. 

figures on the top. The height of the walls of the central 

building was 37 feet, and the Pegasus was 62 feet above 

the ground. The two towers north and south were about 1 8 

feet high, and had each a platform on the top surmounted by 

a pyramidal roof made of triangular boards, which could be 

removed to give a view of any part of the sky. ISTorth and 

south of these observatories were two smaller ones, each 

standing on a single piUar, and communicating with the 




larger ones ; they were also covered with pyramidal roofs, 
and were not built till after the completion of the house. 
Galleries around the towers gave the means of observing 
with small instruments in the open air, and on the east and 
west side of each gallery there was a large globe to serve as 
a support for a sextant. When not in use these globes 
were protected by pointed covers, of which the two eastern 
ones are visible on the figure. This also shows the founda- 

Plas op the Grouot) Floor of Uraniborg. 

A. East entrance. 

B. Fountain. 

C. West entrance. 
". Passages. 

D. Sitting-room in winter. 

E. F, G. Guest-rooms. 
H. Kitchen. 

K. Well. 

L. Stairs to upper storey. 

P. Stairs to laboratory. 

R, 0. Aviaries. 

T. Library. 

W. Great globe, 

S. Cellar for charcoal for the laboratory. 

Z. Wood cellar for kitchen. 

V. Tables. 

Y. Beds. 

4. Chimneys. 

tion- stone in the south-east corner, and next to it a door 
leading down to the basement. 

The south-east room on the ground-floor was the sitting- 
room of the family in winter ; later on it was enlarged by 
pulling down the wall between it and the passage west of 


it. The three other rooms were guest-rooms, but the south- 
west room, in which a large quadrant was attached to the 
west wall, was probably also used as a study. In the storey 
above there were the red room to the north east, the blue 
room to the south-east, the yellow room (a small octagonal 
one) over the porch on the east side, and on the west side 
one long room, the green one, with the ceiling covered with 
pictures of flowers and plants. Tycho specially mentions 
the beautiful view from this room of the Sound, with its 
numerous sails, particularly in summer. Above the second 
storey there were eight little rooms or garrets for students 
and observers. The south tower contained in the basement 
a chemical laboratory with furnaces, &c., above that on the 
ground floor was the library, and above that the larger 
southern observatory. In the north tower the centre of the 
basement was occupied by a deep well built round with 
masonry, which reached to the kitchen above. ■'• Over the 
kitchen was the larger northern observatory. 

In the library the great globe from Augsburg was mounted. 
It was five feet in diameter, the inside made of wooden 
rings and staves firmly held together. When returning to 
Augsburg in i S 7 S j Tycho found that it was not perfectly 
spherical and showed some cracks, but after it had in the 
following year been brought to Denmark, the cracks were 
stopped and the sphericity made perfect by covering it with 
numerous layers of parchment. It was then left to dry 
for two years, and as the figure remained perfect, it was 
covered with brass plates, on which two great circles were 
engraved to represent the equator and the zodiac, divided 
into single degrees, and by transversals into minutes. 
Gradually the stars and constellations were laid down on 
it as their positions resulted from the observations, and not 

1 This well, from which the water could be pumped up and sent to the 
various rooms by concealed pipes, is still in existence. 


till about twenty-five years after the construction of the 
globe bad been commenced was it completely finished.'^ 
It was mounted on a solid stand, with graduated circles 
for meridian and horizon, and a movable graduated quad- 
rant for measuring altitudes. On the horizon was the 
unavoidable inscription stating how the great work of art 
was made. A hemispherical cover of silk could be lowered 
over it from the ceiling to protect it from dust. In addi- 
tion to this great globe, the library or museum contained 
four tables for Tycho's assistants to work at, also his collec- 
tion of books and various smaller knicknacks, portraits of 
astronomers and philosophers, among whom Hipparchus, 
Ptolemy, Albattani, Copernicus, and the Landgrave figured 
conspicuously. There was also a portrait of George 
Buchanan, who played so important a part in the religious 
and political revolutions in Scotland, and whose acquaint- 
ance Tycho had probably made in 1571 when Buchanan 
was in Denmark. This portrait had been presented to 
Tycho by Peter Toung.^ Under the pictures were versified 
inscriptions composed by Tycho.^ 

We may form some idea of the elegance and taste which 
pervaded Tycho's residence by examining the large picture 
which adorned his great mural quadrant. This instrument 
was, as already mentioned, mounted on the wall in the 
south-west room on the ground-floor, and consisted of a 

^ Astr. Inst. Mechanica, fol. G. The globe must have been quite finished 
about 1595 ; it is said to have cost Tycho about 5000 daler (Gassendi, p. 


^ Young had been the first tutor to James VX, and became afterwards his 
almoner. He was several times in Denmark. Tycho had sent his little book 
about the new star to Buchanan, who thanked him for it in a letter dated 
Stirling, the 4th April 1575. In this letter Buchanan (who was then Lord 
Privy Seal) expresses his regret that he has not had leisure to finish his 
poem on the sphere (it was published after his death), and praises Tycho's 
book for having refuted popular errors. 2'. Brahei et ad eum Doct. Vir. Epist, 
p. 18. 

' As specimens Tycho prints the poems on Ptolemy and Copernicus. Epist, 
Astron., pp. 239-240. 



brass arc of 6| feet radius, 5 inclies broad and 2 inches 
thick, fastened to the wall with strong screws, and divided 
in his usual manner by transversals ; it was furnished with 
two sights, which could slide up and down the arc. At the 
centre of the arc there was a hole in the south wall, in 
which a cylinder of gilt brass projected at right angles to 
the wall, and along the sides of which the observer sighted 
with one of the sliding sights. This was one of the most 
important instruments at Uraniborg, and was much used. 
It is,, therefore, no wonder that Tycho (who claimed it as 
his own invention) wished to fill the empty space on the 
wall inside the arc with a picture of himself and the interior 
of his dwelling. Tycho is represented as pointing up to 
the opening in the wall, and he says the portrait was con- 
sidered a very good likeness; at his feet- lies- a dog, "ah 
emblem of sagacity and fidelity." In the middle of the 
picture is a view of his laboratory, library, and observatory, 
and on the wall behind him are shown two small portraits 
of his benefactor, King Frederick II., and Queen Sophia, and 
between them in a niche a small globe. This was an 
automaton designed by Tycho, and showing the daily 
motions of the sun and moon and the phases of the latter. 
The portrait was painted by Tobias Gemperlin of Augsburg, 
whom Tycho had encouraged to come to Denmark ; the 
views of the interior of Uraniborg by its architect, Steh- 
winchel ; and the landscape and the setting sun by Hans 
Khieper of Antwerp, the King's painter at Kronborg. The 
picture bears the date 1587, but the quadrant itself had 
been in constant use since June 1582.-' 

Another instruAient on which Tycho found room for a 
picture was his smallest quadrant, one of the earliest in- 
struments constructed at Uraniborg. The radius of the 

' There are a few meridian altitudes of Spica observed in April 1581, "per 
magnum instrumentum," which probably were also made -with this quadrant. 


quadrant was only i6 inches (one cubitus); the divided arc 
was turned upwards, and within it were forty-four concentric 
arcs of 90° to subdivide the single degrees according to the 
plan proposed by Pedro Nunez. On the empty space be- 
tween the centre and the smallest of these arcs was a small 
circular painting, representing a tree, which on the left side 
is full of green leaves and has fresh grass under it, while on 
the right side it has dead roots and withered branches. 
Under the green part of the tree a youth is seated, wearing 
a laurel wreath on his head and holding a star-globe and a 
book in his hands. Under the withered part of the tree 
is a table covered with money-boxes, sceptres, crowns, coats 
of arms, finery, goblets, dice, and cards, all of which a 
skeleton tries to grasp in its outstretched arms. Above is 
the pentameter, " Vlvimus ingenio, csetera mortis erunt," 
pointing out the vanity of worldly things, while only earnest 
study confers immortality. The first part of the sentence 
is over the green part, the second over the withered part of 
the tree. In another place ^ Tycho had a similar picture, 
in which there appeared among the green leaves symbols 
of the life and doctrine of Christ, while the symbols of 
philosophy are moved over to the withered side under the 
dominion of Death, and the inscription is changed to 
" Vivimus in Christo, csetera mortis erunt," so that the two 
pictures showed the superiority of the noble efforts of the 
human mind over trivial occupations, and yet the insuffi- 
ciency of either except man turns to the Eedeemer. 

This small instrument does not seem to have had any 
fixed place, and was afterwards removed to the subterranean 
observatory, but the larger ones were all erected in the 
observatories at the north and south ends of Uraniborg. 

^ It is not stated where. I conclude from the description in Epistola 
Astron.f p. 254, that these were two different pictures, and not one picture 
seen from two points of view, as one might almost conclude from As'.r. Inst. 
Meoh... fol. A. 


In eack of the two small observatories there was an equa- 
torial armillary sphere, of which the northern one was 
ornamented with pictures of Copernicus and Tycho himself.'' 
In the large southern observatory were the following in- 
struments. A vertical semicircle (eight feet in diameter) 
turning round a vertical axis, and furnished with a hori- 
zontal circle for measuring azimuths (fol. B. 5) ; a tri- 
quetrum, or, as Tycho calls it, " instrumentum parallacticum 
sive regularum " (fol. C.) ; a sextant for measuring altitudes 
with a radius of 5^ feet (fol. A. 5) ; and a quadrant of two 
feet radius with an azimuth circle (fol. A. 4). In the large 
northern observatory were another triquetrum of peculiar 
construction, with an azimuth circle 16 feet in diameter, 
resting on the top of the wall of the tower (foL C. 2) ; a 
sesiant of 4 feet radius for measnriag distances (fol. E.) ; 
and a double arc for measuring smaller distances. Probably 
the last two instruments were removed or used on the open 
gallery when the triquetrum was erected, as the latter must 
have been large enough to fill the whole room, and, indeed, 
even in the southern observatory there cannot have been 
much elbow-room for the observers. In the northern 
observatory was also preserved an interesting astronomical 
relic, the triquetrum used by Copernicus, and made with 
his own hands. 

By degrees, as Tycho's plans for coUecting observations 
became extended and a greater number of young men 
desired to assist him, he felt the want of more instruments 
and of more observing rooms, in which several observers 
could be engaged at the same time without comparing 
notes. In 1584 he therefore built an observatory on a 
small hill about a hundred feet south of the south angle of 
the enclosure of Uraniborg, and slightly to the east. In 

1 Astr. Inst. Mechanica, foL C. 5 (north one) and D. (south one). The first 
observations, "per armillas astrolabicas," are from 1581. References to the 
descriptions and figures of the other instruments are given above in the text. 



this observatory, wticli lie called Stella3burgum (Danish, 
Stjemeborg), the instruments were placed in subterranean 
rooms, of which only the roofs rose above tho ground, so 
that they were well protected from the wind. As shown 
by the view and plan on p. io6, there were five instrunir;rit 
rooms, with a study in the centre, and the entrance to the 
north. The north-east and north-west rooms were built 
somewhat later than the others, and w(;ro nearly at' the 


level on the ground.''- The whole was Kurrourjded by a low 
wooden paling, forming a square with semicircular bends at 
the middle of each side, and the sides facing north, south, 

1 This appears from the stone steps leading «p to the crypt E., Unxml in 
1823, as we shall see in the Appendix. The above figure also shows that not 
only the roofs, but most of the walls of crypts 1). and E. wtre above ground. 
The quadrant in the crypt D. was erected in iJeceinb'rr 1585, twelve monthn 
after Tycho had placed in position the stone on which the lower end of the 
axis of the instrument in crypt C, was supported. When be bad built the 
three crypts, lie p'jrhaps r'-gn.tted having sunk them in tho earth, and there- 
fore built the two new ones higher. 


east, and west. The enclosure was S 7 feet square, and the 
diameter of the semicircles was 20 feet. The entrance 
was on the north side, and a door and some stone steps led 
down to the study. Over the portal were three crowned 
lions hewn in stone, with the appropriate inscription — 



Eelow this and over the door was the coat of arms of the 
Brahe family, and some other allegorical figures. 

On the back of the portal, towards the south was a large 
tablet of porphyry, with a long inscription in prose, stating 
that these crypts had, like the adjoining Uraniborg, been 
constructed for the adyancement of astronomy, at incredible 
labour, diligence, and expense, and charging posterity to 
preserve the building for the glory of God, the propagation 
of the divine art, and the honour of the country. Going 
down the steps to the " Hypocaustum," another slab over 
the door exhibited a versified inscription, expressing the 
surprise of Urania at finding this cave, and promising even 
here, in the bowels of the earth, to show the way to the stars. 
The study was about lo feet square, and only the vaulted 
roof and the top of the walls were above the ground. The 
vault was sodded over to look like a little hill, " represent- 
ing Parnassus, the mount of the Muses," and on the middle 
of it stood a small statue of Mercury in brass, cast from a 
Roman model, and turning round by a mechanism in the 
pedestal.'' The study was lighted by four small windows 
just above the ground, and contained a long table, some 
clocks, &c., and on the wall hung a semicircle in brass, 8 
feet in diameter, for measuring distances of stars, and which, 

' In addition to this, Tycho possessed several other automata, which startled 
the peasants of the island, and made them believe him to be a sorcerer. 
Gassendi, p. 196. 



wlien required, could be placed on a stand outside, similar 
to those wliich Tycho used for Hs sextants. On the ceiling 
was represented the Tychonian system of the world, and on 
the walls were portraits of eight astronomers, all in a re- 
clining posture, namely, Timocharis, Hipparchus, Ptolemy, 

Plan of Stjerneboeg. 

A. Entrance. 

B. Study. 

C. Crypt with large armillae. 

D. „ ,, azimuthal quadrant.' 

E. „ „ zodiacal armillte. 

F. ,, ,, azimuthal quadrant. 

G. „ „ sextant. — 
H, I. Stone piers for portable armillse. 

K, L, N, T. Globular stands for sextants. 
M. Stone table. 
0. Tyoho Brake's bed. 
P. Kreplace. 
V. Table. 

Q. Bedroom for assistant. 
S. Unfinished subterranean passage to- 
wards Uraniborg. 

Albattani, King Alphonso, Copernicus, Tycho, and lastly 
Tychonides, an astronomer who is still unborn. Under 
each portrait was the name, approximate date, and a distich 


setting fortli the merits of each. WMle that under Tycho's 
picture leaves posterity to judge his work, the lines under 
the picture of his hoped-for descendant are less modest, 
expressing the hope that the latter might be worthy of his 
great ancestor. Tycho was represented as pointing up to 
his system of the world, while his other hand held a slip of 
paper with the query, " Quid si sic ? " 

In the centre of each crypt was a large instrument, the 
floor rising gradually by circular stone steps up to the 
walls.-^ The instruments were- an azimuthal quadrant 
(quadrans vohibilis) of S^ feet radius, with an azimuth 
circle at the top of the wall {Mechanica, fol. B. 2), a zodiacal 
armillary sphere (C. 4), a large quadrant of brass (radius 7 
feet) enclosed in a square of steel, and likewise furnished 
with an azimuth circle on the wall (B. 4) ; a sextant of . S-| 
feet radius for measuring distances (D. 5), and in the largest 
southern crypt a large equatorial instrument, consisting of 
a declination circle of 9I feet diameter, revolving round a 
polar axis, and a semicircle of 1 2 feet diameter, supported 
on stone piers, and representing the northern half of the 
Equator (D. 2). In addition to these fixed instruments, 
there were various smaller portable ones kept at Stjerne- 
borg, which could be mounted on the pillars and stands out- 
side or held in the hand ; namely, a portable armilla 4 feet 
in diameter,^ a triquetrum, a small astrolabium or plani- 
sphere, the small quadrant described above, and two small 
instruments made by Gemma Frisius, namely, a cross-staff 
and a circle (annulus astronomicus), both of brass. With 
the exception of these two and the triquetrum of Copernicus, 
all the instruments in Tycho's possession were made in his 

' The number of steps in each crypt may be seen on the plan above. The 
floor of the crypt G (where the sextant was placed) was flat. 

" This was placed either at H or at 7, and served to measure declinations of 
stars near the horizon which could not be got at with the subterranean in- 
struments. See Hpist. Asiron., p. 229. 


own worksiiop, which was situated close to the servants' 
house, about lOO feet to the west.^ 

Tycho would scarcely have been able to construct these 
magnificent instruments if he had not continually been pro- 
vided with new sources of income through the liberality of 
his royal patron. We have seen that Tycho, from February 
1576, enjoyed an annual pension of 500 daler (£1 14). In 
addition to this, the king granted him on the 28 th August 
I 577 the manor of Kullagaard, in Scania, to be held by him 
during the king's pleasure. Kullagaard is situated near 
the north-western extremity of Scania, on the mountain of 
KuUen, which forms a steep promontory in the Kattegat. 
The king's letter stated expressly that Tycho Brahe should 
not, like his predecessor, be bound to keep the lighthouse 
of Kullen in order ; but apparently the king soon found 
that this exemption was a mistake, and already on the 1 8 th 
October 1577 a second royal letter was issued, in which it 
was stated that as the late holder of the benefice had received 
it for the purpose of keeping the light going, in order that 
seafaring men should have no cause for complaint, the same 
should be done by Tycho, if he wished to continue to hold 
the manor.^ This obligation was apparently not to the taste 
of Tycho ; at least he must have been negligent in seeing 
that the light was regularly attended to, for already in the 
autumn of IS79 the governor of Helsingborg Castle was 
ordered to take possession of Kullagaard manor, in order to 
keep the lighthouse properly attended to, as complaints had 
frequently been made about it. As Tycho, however, begged 
to be allowed to keep the manor, on the plea that he had no • 
other place from which to get fuel for Uraniborg, the king 
again granted him the manor on the 13th November 1579, 
on condition that the light was regularly lighted.' In May 

1 In 1577 Tycho had employed a smith at Heridsvad, but he was not able 
for the work. T. B. et Boct. Vir. Epist., p. 42. 

' Ftiis, Tyye Brahe, pp. 80-81. 3 Ibid., p. 96. 


1578 he tad also been granted the use of eleven farms in 
the county of Helsingborg, free of rent, to be held during 
the king's pleasure. These and the Kullen manor he lost 
again for a while in August 1580, probably because he had 
in the meantime been granted other sources of income ; but 
he received them again in June of the following year, " to 
enjoy and keep, free of rent, as long as he shall continue to 
live at Hveen," with the repeated injunction to keep the 
light at Kullen in order. On the 27th October 1581 the 
customs officers at Elsinore were instructed, that whereas the 
light was in future to be kept burning in winter as well as 
in summer, they were out of the increased lighthouse fees 
received from navigators to pay Tycho Brahe 300 daler a 
year for the increase of trouble. This seems, however, to 
have been more than the additional fees amounted to, and 
on the 9th July 1582 the order about the 300 daler was 
cancelled by a royal decree, in which it was stated that 
Tycho was already in receipt of sufficient payment for keep- 
ing the lighthouse.''- In 1584 the governor of Helsingborg 
Castle and the chief magistrate of Scania were ordered to 
proceed to Kullen, together with Tycho, to examine the light- 
house, which was said to be very dilapidated. The tower was 
ordered to be rebuilt in August 1585 at the public expense, 
and at the same time the indefatigable generosity of the king 
dictated a letter to the customs officers at Elsinore, com- 
manding them until further orders to pay Tycho 200 dalera 
annually, in order that the light might be kept burning sum- 
mer and winter as long as navigation lasted.^ 

We have seen that Tycho Brahe already in 1568 received 
the king's promise of the first vacant canoniy in the 
cathedral of Eoskilde. In 1578 this promise was more 
distinctly renewed, as by royal letter, dated Prederiksborg 
the 1 8th May, Tycho was appointed to succeed to the pre- 
1 Friis, Tyge Brahe, pp. 116-117. 2 Ibid., p. 148. 


bend attached to tlie chapel of the Holy Three Kings ^ in the 
said cathedral whenever the holder of it should die. In the 
meantime he was to enjoy the income of the Crown estate 
of Nordf jord in Norway, with all rent and duty derived from 
it.^ He had not to wait very long for the prebend, as 
Heurik Hoik, who had held it since the Eeformation, died 
in 1579, on the 5th June of which year the canonry "was 
conferred on Tycho. In the patent all the temporalities of 
the above-mentioned chapel were granted to Tycho during 
pleasure, including the canon's residence, farms, and other 
property belonging thereto, on the condition that hymns 
were daUy to be sung in the chapel to the praise of God, 
and that for this purpose two poor schoolboys were to be 
kept in. food and clothes in order to assist the vicars-choral 
in the daily service. Furthermore, he was to maintaia. two 
poor students at the University of Copenhagen, and to see 
that these, as well as the two choir-boys, were diligent, and 
fit to devote themselves to learned pursuits. The chapel 
and residence were to be kept in proper repair, and the 
tenants to be dealt with according to law and justice, and 
not to be troubled by any new tax or other impost.^ 

About a month after the prebend had been granted to 
Tycho, he was ordered, in accordance with the rules of the 
chapter, to allow the widow of his predecessor and the 
University of Copenhagen to enjoy annum graticB of the 
rents and other income of the prebend. With characteristic 
coolness the astronomer seems to have turned a deaf ear 
to this injunction, and he even went so far as to forbid 
the tenants to pay anything to the widow. On the 3rd 
December i S 79 the king therefore found it necessary to send 

^ Anglice, the Three Wise Men of the East. The chapel is an excrescence 
on the south side of the cathedral, built in 1464. Among other royal tombs, 
that of Tycho's patron, Frederick II., is in this chapel, 

° Koyal letter, printed in Vanske Magazin, ii. p. 203 (Weistritz, ii. p. 92.) 

^ Ibid., p. 204 (Weistritz, ii. p. 94). 


a second and peremptory order to pay to the widow and the 
University what was due to them.^ Three years later Tyoho 
thought that he saw a chance of making the heirs of Henrik 
Hoik disgorge some of the money he had been obliged to 
let them have, for it appears that some repairs had to be 
made to the chapel, and that Tycho demanded payment for 
thSse from the heirs. But here again the king showed 
that, however favourably disposed he was to the renowned 
man of learning, he would have no injustice done to any- 
body ; and in July 1582 he directed that the repairs were 
to be paid for out of public funds, but that in future Tycho, 
or whoever else might hold the prebend, was to pay for 
them. 2 We shall afterwards see that the possession of this 
prebend gave rise to more serious troubles to Tycho Brahe. 
It was mentioned above that Tycho obtained a grant of 
the Crown estate of Nordfjord on the west coast of Norway, 
to be held by him during the time that he was waiting for 
the vacancy in the prebend. But when he got possession 
of the latter, the king did not deprive him of the Nordfjord 
estate, but granted it to him again on the i3tb June 1579, 
during pleasure, free of rent, and merely with the usual 
stipulation that he was to keep the tenants under the laws 
of Norway, and not injure any of them, nor was he to cut 
down any of the woods on the estate.^ This benefice may 
only have been intended to indemnify Tycho for the year of 
grace which he was to pay out of the Eoskilde prebend, for on 
the 1 0th August 1580 the king's lieutenant at Bergen was 
ordered to receive the Nordfjord estate from Tycho Brahe, 
and in future to account to the king's exchequer for the in- 
come of the same. Tycho must, however, have persuaded the 
king that he could ill afford to lose this income, for already, 

' DansTce Magazin, ii. p. 208 (Weistritz, ii. p. 100). 

^ E. 0. Werlauef, De hdlige tre Kongers Kapel i Roeslllde DomkirJce 
(Copenhagen, 1849), p. 17. 
3 Dans&e Magazin, ii. p. 206 (Weistritz, ii. p. 97). 


on tlie I ith November 1 580, a new grant of the estate was 
made to Tycho in exactly the same terms as the previous 
one, and two months afterwards the lieutenant at Bergen was 
directed to hand over the estate to Tycho Brahe, and to re- 
fund all money received from it during the time he had been 
deprived of it.^ The king evidently now thought that he had 
done enough for Tycho, for on the 29th March i 5 8 1 he wrote 
to him that although Tycho had applied to have the pen- 
sion of 500 daler continued, still, as he had been provided 
for in other ways, the pension was to be paid for the past 
year, but was then to cease. The same day the chief of the 
exchequer, Valkendorf, received instructions to this effect; 
but already six months after he was directed agaiu to pay 
the pension to Tycho, who seems to have received it without 
interruption till 1597.^ 

Tycho continued in undisturbed possession of the Nor- 
wegian estate till March 1586, when he and several other 
tenants of Crown estates in Norway received notice to 
surrender them, as " fish and other victuals " which they 
produced were wanted for the navy. It was, however, 
stated that they were not to consider this as a sign of 
disgrace, but that they would be indemnified in other ways. 
Thus Tycho got in the first instance 300 daler from the 
treasury,^ and on the 1 1 th September following he was 
informed that he would, until further notice, receive an 
annual sum of 400 daler from the customs paid at Elsinore. 
This grant was renewed on the 4th June 1587, the 
money to be paid annually on the 1st May.* The estate 

^ Both letters to the lieutenant are printed in Danske Magasin, ii. pp. 
211-212 (Weistritz, ii. p. io6). 

^ Letter to Tycho Brahe of March 29tb, printed in Friis, Tyge Brahe, p. 
114 ; letter to Valkendorf of same date, in Danske Magazin, ii. p. 217 (Weis- 
tritz, ii. p. 117). 

' Friis, Tyge Brahe, p. 161. 

* Letters of nth September 1586 and 4th June 1587, printed in Danske 
Magazin, ii. pp. 244-245 (Weistritz, ii. p. 165-166), where is also a letter from 


of Nordfjord was restored to Tycho in June i 5 89, and the 
grant was renewed in June 1592, when the allowance from 
the Sound duties was discontinued/ 

It would not at the present time be easy to form an 
accurate opinion as to the actual amount of income enjoyed 
by Tycho Brahe during the years he lived at Hveen (though 
we may mention here that, according to his own statement, 
it was about 2400 daler a year), and on the other hand we 
have no way of knowing exactly how much he spent on his 
instruments and buildings.^ But at any rate, it will be 
evident from the above account of the various grants of 
land and money that King Frederick II. had very amply 
provided for his wants, and never forgot the promises made 
to Tycho when the latter was prevailed on to settle in his 
native country. The circumstances which gradually led to 
his being deprived of most of these grants will be detailed 
in a future chapter ; but we may here mention that Tycho, 
shortly after the death of King Frederick II., in 1588, 
represented to the new Government that his great expenses 
in connexion with the scientific work at Hveen had caused 
him to be in debt to the amount of 6000 daler. This sum 
was at once ordered to be paid by the Government, so that 
Tycho might reasonably hope, even after the death of his 
royal patron, to be able to continue the work so munificently 
supported by the late king. 

Tycho to Niels Bilde, who doubtless then was lieutenant at Bergen, asking him 
to assist Christopher Pepler, formerly Tycho's steward at Nordfjord, to get 
payment for some money still dae to him. 

' Friis, p. 180; Danske Magazin, ii. p. 280 (Weistritz, ii. p. 228). 

' Tycho in 1598 estimated the total cost of all his buildings and instru- 
ments at 75,000 daler (about ;^i 7,000). See below, Chapter X. 



At Uraniborg Tycho spent more than twenty years, from 
the end of i 5 7 6 to the spring of 1597, the happiest and 
most active years of his life. Surrounded by his family 
and numerous pupils, many of whom came from great 
distances to seek knowledge in the house of the renowned 
astronomer and assist him in his labours, frequently 
honoured by visits from men of distinction both from 
Denmark and abroad, Tycho during these years steadily 
kept the object in view of accumulating a mass of observa- 
tions by means of which it would be possible to effect that 
reform of astronomy which was so imperatively demanded, 
and for which the labours of Copernicus had merely paved 
the way. But though the scientific work was never 
neglected, the pleasant little island afforded many means 
of recreation. The map in Braun's Theatrum Urbium 
shows that provision was made for games of various kinds 
in the orchards which surrounded Uraniborg, and ia the 
south and east of the island there were places arranged 
for entrapping birds. There were plenty of hares and 
other small game, and Tycho caused a great number of 
fishponds to be made. Most of them lay in the south- 
western part of the island, connected by sluices into two 
rows which met in a lake, the second largest of all, from 
which a small river made its way through the cliflF to the 

sea. On this spot Tycho afterwards built a paper-mill. 



Xone of these fistponds are seen on Braun's map, and tliey 
would therefore seem to have been constructed after 1585, 
as the map bears the date 1586. Thus Tycho contrived to 
add to the comfort and convenience of his surroundings. 

In addition to these means of recreation, Tycho Brahe 
possessed others of a higher kind. In 1584, the same 
year in which the Stjerneborg was built, he put up a 
printing-press in the buUding at the south angle of the 
enclosure surrounding Uraniborg. It was originally in- 
tended for the printing of his own works, but when not 
required for this purpose he occasionally employed it to 
priut poems in memory of departed friends, and similar 
poetical effusions. Thus we have already mentioned that 
in 1584 he printed an epitaph of his friend Pratensis,^ 
and in the same year he printed a poem addressed to a 
Danish nobleman, Jacob UKeld, to give the printer some- 
thing to do, as he informs us.^ Of greater interest is a 
longer poem of 288 lines, dated the 1st January 1585, and 
addressed to the Chancellor, Niels Kaas.^ In this Tycho 
complains of the neglected state of astronomy in most 
countries, and contrasts this with its present flourishing 
state in Denmark, where buildings have been erected and 
iostruments constructed such as the world never saw. But 
envy and malice attempt to speak slightingly of this great 
work, and he might almost be inclined to regret having 
undertaken it and look for another home elsewhere,* if he 

1 A poem in memory of another friend, Joh. Francisci Ripensis, giren in 
Gassendi's book, p. 261, was possibly also printed at Uraniborg. 

- Printed in Danske Magazin, ii. pp. 223-224 (Weistritz, ii. p. 130 ct seq.). 

' Printed ibid., pp. 226-234 (Weistritz, ii. 135 et seq.). 

* " Undique Terra infra, ccelum patet undique supra, 
Omne solum patria est, cui mea sacra placent." 

Tlie first of these lines and part of the second occur in Astr. Instaurata 
Mechania, fol. D., Vfhere he mentions that one of his armillae could be taken 
asunder and transported to any place where it might be wanted. It is 
remarkable how strongly imbued he always was with the cosmopolitan 
character of his science, even when Fortune smiled most on him. 


did not remember that tlie Chancellor was interested in it for 
the sake of the honour thus conferred on his country, and 
would therefore continue to protect it. Another but shorter 
poem was soon afterwards printed at Uraniborg, addressed 
to the learned Heinrich EantzoT, governor of the Duchy of 
Holstein. In this poem, which is dated the 1st March 
1585, Tycho complains that Eantzov, in a book on astro- 
logy which he had just published, had used the word 
specula when speaking of Uraniborg, which magnificent 
building did not merit so mean an appellation.''- 

The considerable building operations in which Tycho 
engaged at Hveen obliged him, to require a great deal of 
work from his tenants there, and when we remember his 
naturally hot temper, and his habit of exacting without 
scruple what was due to him (and even more, as in the case 
of Hoik's widow), it is not to be wondered at that com- 
plaints were more than once made by the tenants at Hveen 
of his arbitrary treatment of them. Already on the 1 0th 
April 1578 an order was issued by the king to the 
peasants at Hveen, that they were not to leave the island 
because Tycho Brahe required more labour than had formerly 
been demanded from them.^ But Tycho, who was perhaps 
not worse (and certainly not better) than his fellow-nobles 
were generally in the treatment of their inferiors, continued 
in the following years to make such great demands on the 
peasantry at Hveen to get his buildings, plantations, fish- 
ponds, &c., finished, that fresh complaints were made. The 
king therefore sent two noblemen, the governor of Helsing- 
borg Castle and the governor of Landskrona Castle, to 
Hveen to investigate matters. When these two officials 
had presented their report, the king, on the 8th January 
I 5 8 1 (the same day on which he ordered his lieutenant at 

1 Printed !a Danslce Magazin, ii. pp. 235-238 (Weiatritz, ii. p. 148 et seg-). 
' Friis, Tyc/e Bralie, p. 89. 


Bergen to restore the Norwegian estate to Tycho), issued 
an ■■ Arrangement and rule for Tyclio Brahe and the in- 
habitants at Hveen," which both parties were ordered to 
obev and follow.^ In this document the amount of labour 
to be famished by each farm was fixed at two days a week, 
from sunrise to sunset, and rules were laid down about 
Tarious other matters ; thus a tenant who did not keep his 
dikes and fences in order was to pay a fine in money to the 
landlord and a barrel of beer to the townsmen ; nobody 
was to gather nuts or cut wood without leave from Tycho 
Brahe or his steward ; a petty sessions court was to be held 
every second Wednesday," and appeals were to be heard in 
Scania in future, instead of in Seeland.* The peasants 
were not to consider their holdings as their own property, 
as they had no legal authority for doing so, but in future, 
when any farmer died, his holding was to be treated as any 
other farm on a Crown estate. 

If the buildings and other works at Hveen required 
mach manual labour, the scientific researches for the sake 
of which they were erected required a great deal of work 
to be done by practised observers and computers, and these 
Tycho readily found in the young men who soon began to 
flock to Hveen in order to enjoy the privilege of studying 
under his guidance. The first to arrive seems to have been 
Peder Jakobsen Tlemlose, born about I ^^4. in a villasre 
called Flemlose, in the island of Fyen (Funen). He had 
already, in 15 74, published a Latin poem on the solar 
ecKpse of that year, in which he showed that though eclipses 
have a perfectly natural cause, they are signs of the anger 
of God ; but the eclipse of I 574 he believed to mean that 
the second coming of Christ was soon to take place. This 

^ Printed in Danske ilagizin, ii pp. 213-217 (Weistritz, ii. pp. Iio-i!6). 
- The conrt was held on a hill close to Uraniboi^ / on the map). 
^ This does not seem to have been carried out. See above, p. SS. 


little book lie dedicated to Tycho Bi-alio.' IIo sopins to 
liave studied medicine in liis youth, for liis second publica- 
tion, in IS 75. was a translation of Simon Mnsanis' book 
against melaucLoly. He must liavc entered Tycbo's scrvieo 
in tbe beginning of 1578, and did so (according to Longo- 
montanus) on account of tbe supposed intimate conucclion 
between medicine and astronomy.^ That Tyclio bad great 
confidence in bim may be soon from tbe fact ibat be sent 
bim to Cassel in i 586 to dolivor a letter to tbe Landgrave 
and report to Tj^cbo on tbe new instruments lately mounted 
tbere. In June 1579 be received by royal letter a 
promise of tbe first vacant canonry in Roskiklo Catbedral, 
on condition tbat "be sball be bound to let bim self be 
used in stndiiH matJiematicin at Tyge Brabe's." lie bail, 
bowever, to ^^'ait a long time for Ibis reward of bis services 
at liveen, as be did not obtain tbe canonry till i 590, when 
be bad left Tycbo, after more than ten' service in tlie 
observatoiy, and bad become physician to Axel Gyldenst jern, 
one of the two noblemen whom the king bad sent to livern 
to report on tlio affairs of tbe tenants, and who bad since 
been made Governor-General of Norway. Flemlose died 
suddenly in 1599, just when about to proceed to Basle to 
obtain tbe degree of Doctor of Medicine.* Wbei;her his 
medical studies had derived much benefit from bis astro- 
nomical labours is not known, but while at Uraniborg, be 
not only spent bis time on "pyronomic" {i.e., chemical) 
and astronomical matters, but also coniink'd a little book- 
which was printed tbere in 1591, sonie years after bis 

' "^cloga de eolipsi Bolari anno 1574 mense Novembri fiitnra et tempore 
plenilunii eoliptioi anno 1573 conspeoti, Sucoularum ortu obiter descripto, 
breuique Melibcjui pastoris querela. . . , Autore Potro Jaoobo riemloBnio." 
Hafuias, 1574, 4ti). 

- He made observations with tlin s(^xtiint on tlie 15th Maroli 1578, and tlie 
distance measures on and after January 21 are pos«n)ly also by hini, 

' See N. M. I'utersen, Den Danske Utcrulnra Jlislorir, iii. pp. 176-179, and 
tlie preface by Friis to tlie reprint of Flemlose's book (1865). 


departure, containing 399 sliort rules by whicli to foretell 
changes in tke weather by the appearance of the sky, the 
sun, moon, and stars, or by the behaviour of animals."' In 
the absence of the author, the introduction was written in 
his name by his fellow-student, Longomontanus, at the 
dictation of Tycho. In this it is stated that King Frederick 
took a great interest in weather prognostications, and had 
desired Tycho Brahe, from books and his own experience, to 
compile a treatise on the subject, but as Tycho had other 
and more important work to look after, he had requested 
Flemlose to do so. It is not said whether the author had 
collected his materials at Hveen, but most of the rules 
contained in the book are chiefly such as farmers and 
similar observers might imagine they had deduced from 
their experience, and here and there it affords curious 
reading, at least to a modem student.^ 

Another of the early assistants of Tycho was a German, 
Paul Wittich, from Breslau, whose name, but for his early 
death, would probably be much better known in the history 
of astronomy than it ' is. He had been recommended by 

^ "EnElementisch or Jordisch JsiroZo^ia Om Lufftens forendring. . . . Til- 
sammen dragen aff Peder Jacobson Flemlos paa Hueen. Prentit paa Vrani- 
borg Aff Hans Gasohitz, Anno 1591," xvi. + 143 pp., i2mo. Reprinted at 
Copenhagen in 1644 (by Longomontanus), 1745, and 1865. According to 
Friis, Tyge Brahe, p. 362, a German translation was printed at Hveen in 
September 1 591, of which there is a copy in the library of the Polytechnic 
Institute at Vienna (see also Kepleri Opera, viii. p. 705, first line). 0£ the 
Danish original, only two copies are Icnown to exist, both at Copenhagen. 

2 I shall give a few examples : — Flies and fleas announce rain when they 
are more than usually troublesome to men, horses, and cattle (ccv.). When 
goats are so very greedy that you can neither by words nor blows drive them 
away from small shrubs, which they bite off though they are not very hungry, 
then it is a sure sign of rain or storm (ccix.). When pigs with their snouts 
are throwing sheaves of corn or bundles of straw round about as if they were 
mad, you need not doubt that there will soon be rain (ccxxii.). All kinds of 
unusual fire in the air, appearing like an army or like stars running to and 
fro or against each other, or falling down to the earth, are forewarnings of 
comets (ccolx.). [This looks like an unconscious anticipation of modern ideas 
about the nature of comets.] Earthquakes generally follow after great and 
long-continuing comets (ccclxiii.). 


Hagecius, and arrived at Hveeii in the summer of I 580, 
where he took part in the observations of the comet of that 
year from the 21st to the 26th October.^ He showed him- 
self a very able mathematician, according to Tycho's own 
testimony,^ and declared it to be his wish to stay at Urani- 
borg and be a " fidus Achates " to Tycho. But when he 
had been about three months at Hveen, he announced that 
he Jiad to go home to Breslau, as a rich uncle of his was 
dead and he wanted to secure the inheritance, but he would 
return to Hveen in seven or eight weeks. He took with 
him a letter from Tycho to Hagecius (dated 4th November 
1580), and Tycho became very uneasy when he neither 
heard anything from Wittich (who never returned to Hveen) 
nor received an answer from Hagecius for more than a year. 
He learned at last, in 1582, that the letter had been duly 
delivered.^ A few years after he heard that Wittich had, 
about 1584, turned up at Cassel, where his descriptions of 
Tycho's improvements in instruments, particularly of the 
sights and the transversal divisions, as well as of Tycho's 
sextants for distance measures, created so great a sensation 
that the Landgrave immediately had his instruments im- 
proved and altered by his mechanician, Joost Blirgi, in 
accordance with Wittich's descriptions.* When Tycho 

^ In the observations (Tyclionis Brake Ohservaliones Septcm Cmnetarum, 
Hafnise, 1867, p. 30) there is a note written in October 1600, and signed Jacob 
Monaw, certifying that the observations of October 21st to 26th were written 
in Wittich's hand. I find in Jocher's Gelehrten Lexicon that this Monaw was 
a Jesuit from Breslau (1546-1603), where he had evidently known Wittich. 

- In Tycho's MecJianica, fol. I. 3, he is mentioned as " quidam insignia 
mathematious," and in Progymn., ii. p. 464, he is called "quidam Vratislauien- 
sis non vulgaris Mathematious. " In a letter to Rothmann {Bpist. Astr., p. 61 ) 
Tycho says that Wittich ingratiated himself with him "quod homiuem ob 
ingeniosam in Mathematicis, prsesertim quo ad Geometriam attinet, solertiam 
magnifacerem." We shall see farther on that Tycho and Wittich together 
deduced convenient formulte whereby multiplication and division of trigone 
metrical quantities were avoided. See also Epist., p. 296. 

^ T. Brake et Doct. Vir. /.'pislola, pp. 54, 58, 64. 

* Epist. Astron., p. 3. 


learned tliis lie was extremely annoyed, and seemed to think 
that Wittich had pretended to be the inventor of all he had 
described to the Landgrave (although the latter had not 
said so), and in his first letter he took care to tell the 
Landgrave that "Wittich had seen all these things at Hveen, 
as might already be seen from the word " sextant." ^ How 
long Wittich remaiQed at Cassel is not known; he was 
there in Kovember 1584, when he observed a lunar eclipse, 
and the Landgrave's astronomer, Eothmann, mentions him 
in a letter of April 1586 as having left a good while 
previously. He died on the 9th January 1587," and 
Tycho seems on learning this to have regretted that he had 
suspected Wittich of robbing him of his fame, for he wrote 
in August 1588 that he would have written more mode- 
rately about him had he known he was dead.' Though 
Wittich spent but a short time at L'raniborg, his name 
deserves to be remembered by astronomers, as he was 
apparently the ablest of all Tycho's pupils.* 

Most of these pupils spent a much longer time at Urani- 
borg than Wittich had done. Thus Gellius Sascerides 
stayed about six years there. He was born at Copenhagen 
in 1562, and was a son of Johannes Sascerides of Alkmaar, 
in Holland, professor of Hebrew in the University of 
Copenhagen. Gellius had studied at Copenhagen and at 
Wittenberg, and came to Hveen early in 1582, where he 

1 Ibid., p. 7. 

- According to a M3. in the library at Breslau, quoted by Rud. Wolf in 
the Tiertdjahrsschrift dcr Astron. Gcsdlschaft, svii. p. 129. 

■* Epi&t. Jstron., p. 1 13. Tycho here again praises his cleverness "in 
Geometricis et Triangulorum ac nnmerorum traotatione." In the letter of 
20th January 15S7 (to which he refers) he had, after all, only said : " Si mea 
inventa . . . pro suis venditat, nee fatetur per quern ea habuerit, rem a viro 
bono et grato, ac sinceritate integritateque Mathematica alienam committit." 

■* In Chalmers' General B'logr. Dictionary, London, 1815, ^**^* ^^- P- 243, it 
is stated, on the authority of a Life of the Scotch mathematician Duncan 
Liddel by Prof. Stuart (1790), that Liddel studied mathematics at Breslau, 
I5S;-S4, "under Paul Wittichius, an eminent professor." 


remained until 1588, when he went abroad to continue his 
medical studies in Italy. Tycho gave him a letter for 
Eothmann, to whom he recommended Gellius as having 
assisted him both in astronomical and in chemical work."- 
We shall afterwards hear how he and Tycho got on 
together after his return. 

We know much less about another assistant who observed 
at Hveen about the same time as Gellius, called Elias Olsen 
Cimber (or Morsing, i.e., from the Isle of Mors, in the 
Limfjord), although he must have spent a number of years 
with Tycho. When he first came to Hveen is not known, 
but he seems to have been there in April 1583, when his 
handwriting is believed to occur in the meteorological 
diary. This diary (of which the original is now in the 
Hofbibliothek at Vienna) was regularly kept from the 1st 
October 1582 up to the 22nd April 1597, about the time 
when Tycho left Hveen for ever.^ It contains for every day 
short notes about the weather, stating whether it was clear 
or cloudy, hot or cold, rainy or dry, &c. These notes are 
always written, in Danish, except where halos, auroras, or 
similar phenomena are described, which is generally done 
in Latin. But the principal interest attached to this diary 
arises from the numerous very short notes about the arrival 
or departure of Tycho, his pupils or visitors, which occur 
frequently from April 1585. These historical notes are 
always written in Latin ; they are often very much abbre- 
viated and difficult to decipher. This diary, which forms a 
most interesting record of the life at Hveen, was kept now 

' Bpist. Astron., p. 104. 

^ It was published at Copenhagen in 1876 : Tyge Bralie^s meteorolotjisJce 
Daghog holdt paa Uranihorg for Aarene 1582-1597. Appendice anx Collec- 
tanea Meteoi-ologica publics sous les auspices de VAcadSmie JRot/ale des Sciences 
et des Lettres d Copenkague. The A'alue of the diary (263 pp. 8vo) is greatly 
increased by an index to the historical names by a Danish historian, H. F. 
Rordam. There is also a discussion of the meteorological results by P. la 
Cour (with a French resum^). 


by one, now by another assistant (though their names are 
not given), and a great deal of it was written by the above- 
mentioned Elias Olsen, whose writing appears in it for the 
last time in April 1589. Probably he left Tycho's service 
at that time, as he is mentioned in the diary as having 
arrived and departed several times after that date. 

In 1584 Elias Olsen was sent by Tycho on an astro- 
nomical expedition of some importance. At Hveen the 
inclination of the ecliptic had been found equal to 23° 31'. 5, 
while Copernicus had found 23° 28'. Tycho correctly ex- 
plained this by pointing out that Copernicus had measured 
the meridian altitudes of the sun at the summer and winter 
solstices without taking refraction into account, and for the 
latitude of Frauenburg in Prussia this would at the winter 
solstice cause an error of over 4' in the altitude. Tycho, 
however, believed the solar refraction at the altitude of i 2° 
to be equal to 9' ; but, on the other hand, he assumed with 
Copernicus, that the solar parallax was 3', so that one mis- 
take is somewhat compensated by the other. He had also 
found that the solar theory of Copernicus often deviated 
considerably from the observed places of the sun, and he 
suspected that Copernicus had reduced his solar observations 
with an erroneous value of the latitude. He, therefore, 
gladly took an opportunity of verifying this latitude when, 
early in 1584, an embassy from George Frederic, Margrave 
of Ansbach,^ headed by a nobleman of the name of Levin 

^ He was at Hveen June 9 to 11, and July i to 3, 1589, November 5 to 
March II, 1590. Under the last date the printed edition has " Elias obiit H. 
1 1^ noct.," but doubtless the original has aiiit and not ohiit^ for the words 
"Elias Olai " occur again on the 8th May 1596, so he cannot have died in 
1590. In 1589 he went with "Vedel on a tour through Denmark to observe 
latitudes and azimuths for Vedel's topographic survey of the country. See 
E. 0. Uorsing og hans Observationer, af F. R. Friis, Copenhagen, 18S9, 28 pp. 

^ Regent of the Duchy of Prussia (for his cousin, Duke Albrecht Frederic, 
who was insane). The house of Hohenzollern is descended from him. 


Billow, returned to Germany after having carried out its 
mission to the Danish Court. As the embassy was sent to 
Dantzig in some royal ships, it was easy for Tycho Brahe 
to obtain permission for Elias Olsen to make the voyage on 
one of these. He happened to be keeping the meteoro- 
logical diary at that time, and continued on the journey to 
record in it the state of the weather. We learn thus that 
he started from Copenhagen on the ist May, reached 
Dantzig the i oth, and Frauenburg on the 1 3th. In this 
quiet little cathedral town Copernicus had lived many 
years, engaged solely in building up his great astronomical 
work, and only now and then turning aside from this to 
assist with his clear mind in the government of the little 
diocese-principality of Ermland or in the affairs of the 
chapter of Frauenburg. Elias Olsen remained on this clas- 
sical spot from the 1 3 th May till the 6th June, and, with 
a sextant which he had brought with him, he found by 
meridian altitudes of the sun and stars the latitude to be 
54° 22^', while Copernicus made it 54°I9-|-' (the modern 
value is 54° 21' 34")- Tycho remarks that the solar decli- 
nations of Copernicus are consequently 2^' in error, which, 
together with his omission of refraction, was sufficient to 
explain the shortcomings of his solar theory. We shall 
afterwards examine this question again when discussing 
Tycho's labours on the solar theory. While Elias Olsen 
was at Frauenburg he was requested to determine the lati- 
tude of Konigsberg, and went there on the 8th June. He 
found 54° 43', greatly different from 54° 1 7', which Erasmus 
Eeinhold had assumed in the Prutenic tables on the autho- 
rity of Apianus.^ On the 28th June Elias left Konigsberg 

^ Progymnasmata, pp. 34-35 ; Epist. Astr., p. 74. The latitude of the 
Konigsberg observatory is 54° 42' 51". Most of the observations made at 
Frauenburg are given in Baretti Ilistoria Coelestis, p. 104, and are correctly 
reproduced, except that the date of the observations of May 1 1 should be 
May 17. In the Hist. Ccel. are not given the " Observationes factse in 


for Franenbnrg, spent five days there, departed for Dantzig 
on the 4tli July, started from thence on the 7th, and was 
back at Hveen on the 2 3rd.'^ 

Valuable as these results of the journey were, Elias 
brought something else home with him which was perhaps 
even more valued by Tycho. One of the canons at Franen- 
bnrg, Johannes Hannov, sent him the instrument used by 
Copernicus and made by his own hands. It was a triqne- 
trum eight feet long, made of pine-wood, and divided by 
ink-marks, the two equal arms into 1 000 parts, the long 
arm into 14 1 4 parts. Tycho placed this scientific relic in 
the northern observatory at Uraniborg, and the very day he 
received it (the 23 rd July) he composed a Latin poem ex- 
pressing his enthusiastic delight at possessing an instrument 
which had belonged to this great man, whose name he never 
mentioned without some expression of admiration.^ This 
feeling he also gave vent to in the poem which he a few 
months later wrote and placed under the portrait of Coper- 
nicus in his library. Possibly he had received this portrait 
on the same occasion as the instrument.^ 

The name of Elias Olsen is also connected with the first 
book printed at Uraniborg, an astrological and meteorolo- 
gical diary for the year 1586, somewhat similar to the one 
drawn up by Tycho for the year 15 73- It ^'Iso contains an 
account of the comet of 1585, which had been observed at 
Hveen from the i8th October to the i 5 th November. The 
little book is dated the 1st January 1586, and is dedicated 

^dibns HortensibuB illustrissimi Marchionis duels Borussise Kegiomonti ; " 
they are similar to those made at i"rauenburg, and extend from June Ii to 26 
(IIS. Tolume of Obs.). 

^ The dates are from the meteorological diary. Friis {T. Brake, p. 133) 
tells his readers that Elias went to Regensbnrg (Regiomontnm !!) without 
remarking the wonderful speed with which he would have had to travel to 
reach Regensburg from the shore of the Baltic in less than two days. 

- £piet. Aatr., p. 235 ; Gassendi, p. 57. 

' Epitt., p. 240. 


to tlie Ci'own Prince, who was then between eight and nine 
years of age.-^ 

Of Tycho's other pupils, Longomontanus is the best 
known. Christen Sorensen Longberg was born on the 4th 
October i 562, at the village of Longberg or Lomborg, in 
the north-west of Jutland, where his father was a poor 
farmer.^ When his father died in 1 570, his uncle took 
charge of him for some time, but as the means of the family 
were too small to allow the boy to follow his inclinations and 
go to school, the uncle sent him home to his mother to help 
her on the farm. The boy persuaded the mother to allow 
him to get some lessons during the winter-time from the 
clergyman of the parish, but during the summer he had to 
lay aside his books and take to farming again. At last he 
got tired of this, and in the spring of 1577 he took his 
books, and, without telling any one, walked off to the town 
of Viborg, some fifty miles from his home. He attended the 
grammar-school of Viborg for eleven years, and in addition 
to the ordinary school course of those days he learned the 
rudiments of mathematics. At the age of twenty-six he left 
the school for the University of Copenhagen, and the fol- 
lowing year (1589) he was, on the recommendation of 
some of the professors, received as an assistant at Uraniborg, 
where he remained till 1597, when he left it together with 

Of most of the other young men who for a longer or 

^ " Diarium astrolngicum et metheorologioum anni anatn Christo 1586. Et 
de Cometa qvodam rotnndo omniqve cavda destitute qui anno proxime elapso, 
mensibus Octobri et Nouembri conspiciebatur, ex observationibus oertis de- 
sumta consideratio Astrologioa : Per Eliam Olai Cimbrum, Nobili viro 
T^ohoni Brahe in Astronomicis exercitiis inservientem. Ad Loci Longitudi- 
neui 37 Gr. Latitudinem 56 Gr. Excusum in Offioina Vranibvrgica." See 
Weidler, Hist. Astr., p. 623 ; Petersen, Danslee Literaturs Historic, iii. p. 180. 

^ West of the town of Lemvig, about four miles from the west," coast. lu 
Latin, Longberg called himself Christianus Severini Longomontanus. 

^ Petersen, DansTcc Literaturs Historic, iii. p. 177. 


shorter time assisted Tyclio Brahe, we know little but the 
names. A certain Ilans Coll, or Johannes Aurifaber, who 
had charge of the workshop, must have been with him a 
long time, as he is mentioned as observing in 1585, and 
he died at Hveen in 1591/ Many details as to the life at 
Hyeen were communicated to Gassendi by Willem Janszoon 
Blaev, the celebrated printer at Amsterdam, who in his 
youth (he was born at Alkmaar in 1571) had spent a few 
years at Hyeen, and to whom we also owe the large map of 
the island in his son's Grand Atlas. ^ 

Two other inmates of Tycho's house may also be men- 
tioned here. One was a maid of the name of Live (or 
Liuva) Lauridsdatter, who afterwards lived with Tycho's 
sister, Sophia, and later was a sort of quack-doctor at 
Copenhagen, where she also practised astrology, &c. She 
died unmarried in 1693, when she is said to have reached 
the ripe age of 1 24.^ The other was his fool or jester, 

^ Observatwnes '^cptem Cometarum {1867), pp. 63-64; Baretti Historia 
C(£lestis, p. 429; Diary, 30th November 1591. 

^ The map was made "cum sub Tychoiie Astronomise operam daret." 
Blaev must have been at Hveen during the last few years of Tycho's residence 
there. He is mentioned in the Observations of Cornels, p. 41, as being there 
in 1596. For a list of Tycho's other disciples and assistants, as far as their 
names are known, see jN"ote B. at end of this volume. In 1589 Eothmann 
inquired, on behalf of Professor Victor Schonfeld of Marburg, whether 
Tycho would receive a son of Schonfeld among his pupils, adding that the 
young man had just been made a Master of Arts ; to which Tycho answered 
that he might come, but whether he was a master or not did not make much 
difference, that it was better to be a master than to be called one, and it would 
be sufficient if he was a student of the free arts (Epist., pp. 154, i68). In 
Wolf's Encomion Eegni Danice, 1654, p. 526, it is stated that there were 
Bmall bells in the rooms of the students, which could be rung by touching 
hidden buttons in the observatories or sitting-rooms, by which Tycho, to 
the surprise of his guests, could make any of the students come to him, appa- 
rently merely by calling their name in a low voice. Wolf also tells how Tycho 
could lie in bed and observe the stars through a hole in the wall, with some 
mechanism which could be turned round. Probably this refers to the mural 
quadrant, which had a " hole in the wall." 

' Kastner, Gesch. der Math., ii. p. 408, quoting Nova Literaria Maris 
Balthici, August 1698, p. 142. There is a portrait of this woman in the 
National Historical Museum at Frederiksborg Castle. 


a dwarf called Jeppe or Jep, who sat at TycWs feet when 
he was at table, and got a morsel now and then from his 
hand. He chattered incessantly, and, according to Longo- 
montanus, was supposed to be gifted with second-sight, and 
his utterances were therefore listened to with some atten- 
tion. Once Tycho had sent two of his assistants to Copen- 
hagen, and on the day on which they were expected back 
the dwarf suddenly said during the meal, " See how your 
people are laving themselves in the sea." On hearing this, 
Tycho, who feared that the assistants had been shipwrecked, 
sent a man to the top of the building to look out for them. 
The man came back soon after and said that he ha-d seen 
a boat bottom upwards on the shore, and two men near it, 
dripping wet. Whenever Tycho was away from home, and 
the pupils relaxed their diligence a little, they set Jeppe to 
watch for him, and when the dwarf saw Tycho approach 
he would call out to them, " Junker paa Landet," i.e., the 
squire [is] on land.^ "When any one was ill at Hveen, and 
the dwarf gave an opinion as to his chance of recovery or 
death, he always turned out to be right. 

There was plenty to do for all the young men at Urani- 
borg. Of course the astronomical work was always their 
principal occupation, but the laboratory was also in con- 
stant use. We have no knowledge of the particular direc- 
tion of Tycho's chemical researches, but that he always took 
a very deep interest in chemistry is evident from more than 
one allusion to this subject in his writings. In several of his 
books are found a pair of vignettes, which illustrate the view 
of Nature as a whole, representing one idea under various 

' Gassendi (p. 197), who had these details from letters written to him and 
Peyresc by the Danish physician and historian Ole Worm, has misspelt the 
exclamation of the dwarf as " Junoher xaa laudit." See also 0. Wormii et 
doct. vir. ad eum Epistolce, Hafniae, 1751, and Gassendi, Epistolcs (Opera, 
vol. vi.), p. 527, where the name is misspelt Leppe. The word "Junlier" 
(esquire), which always is used of T. Brahe, shows that he was not a kniglit. 


aspects, with wliicli not only Tycho, but most tbinkers of the 
Middle Ages were imbued. ■"• On both these vignettes is seen 
a man in a reclining posture, with a boy at his side ; but in 
the one case the man is leaning on a globe and holds a pair 
of compasses in his hand, while his face is turned upward ; 
in the other case he has at his side some chemical apparatus, 
and holds in his hand a bunch of herbs, while the snake of 
^sculapius is coiled round his arm, and he is looking down- 
wards. At the sides of the former picture is the motto, 
" Suspiciendo despicio ; " round the latter, " Despiciendo sus- 
picio," expressing beautifully the mystical reciprocal action 
and sympathy between the " sethereal and elementary worlds." 
In a letter to Eothmann, Tycho enters at some length on 
this subject, but his remarks contain nothing which may 
not be read in any book of the time in which the " occult 
philosophy " is taught, and we have already sufficiently 
alluded to these matters in previous chapters. He mentions 
the principal authors whom he has followed,^ but adds that 
Paracelsus has truly said that nobody knows more in this 
art than what he has experienced himself per ignem, for 
which reason he cultivates the " terrestrial astronomy " with 
the same assiduity as the celestial. In the laboratory Tycho 
also occupied himself with the preparation of medicine, and 
as he distributed his remedies without payment, it is not 

^ These vignettes seem first to have been used for a poem to a friend of 
Tycho's, Falk Gjoe, printed at Uraniborg between 1584 and 1587, and of 
which I am not aware that any copy now exists. Kothmann came across a 
copy at Frankfurt, and asked Tycho to explain the vignettes. Epist. Astron., 
p. 89; Tycho's reply, ibid., p. I15-I17. 

2 Among these are Hermes Trismegistus, Geber, Arnoldus de Villa Nova, 
Raymundus LuUius, Thomas Aquinas, Roger Bacon, Albertus Magnus, &c. 
He does not allude to the fact that the idea expressed in the two vignettes 
occurs already in the second of the thirteen sentences of the so-called Hermes 
Trismegistus : " What is below is like what is above, and what is above is 
like what is below, to accomplish the miracles of one thing " (see Nature, vii. 
P- 90). There is, however, an allusion to this sentence in Epist. Astron,, 
p. 164. 



strange that numbers of people are said to have flocked to 
Hveen to obtain them.i In the official Danish Pharmacoposa 
of 1658 several of Tycho's elixirs are given, and in 1599 he 
provided the Emperor Rudolph with one against epidemic 
diseases, of which the principal ingredient was theriaca 
Andromachi, or Venice treacle, mixed with spirits of wine, 
and submitted to a variety of chemical operations and ad- 
mixtures with sulphur, aloes, myrrh, saffron, &c. This 
medicine he considered more valuable than gold, and if the 
Emperor should wish to improve it still more, he might add 
a single scruple of either tincture of coral or of sapphire, of 
garnet, or of dissolved pearls, or of liquid gold if free from 
corrosive matter. If combined with antimony, this elixir 
would cure all diseases which can be cured by perspiration, 
and which form a third part of those which af&ict the human 
body.^ This prescription Tycho begged the Emperor to 
k£)ep as a great secret, and he had evidently as much con- 
fidence in the powers of his elixir as the ingenious Hidalgo 
of La Mancha had in the efficacy of his celebrated balsam. 

We can form some slight idea as to the principles which 
guided Tycho in his medical practice from a remark in one 
of his letters to Rothmann, where- he speaks of the Aurora 
Borealis. This he takes to be sulphurous vapour, indicat- 
ing that the air is apt to engender infectious diseases, " for 
such illness has a good deal in common with the nature of 
sulphur, and it can therefore be cured by perfectly pure 
earthly sulphur, particularly if this is made into a pleasant 
fluid, as like cures like {tanquam siinile suo simili), for the 

^ Tycho seems to have had an apothecary in his service, as Paulus Phar- 
macopola is often alluded to in the diary ; e.g., 22nd July 1596 : " Elisabetha, 
filia Pauli pharmacopolse, Joachimus et Theodoricus propter seditionem 

2 The prescription is printed by Gassendi, p. 242 et seq. ; he had it from 
Worm, who in 1653 informed Gassendi that the elixir was still much used in 
Denmark, frequently by the writer himself, who found it to be most powerful 
in causing perspiration (Opera, vi. p. 526), 


principle of the Gallenians, contraria contrariis curari, is not 
always true." ■*■ 

We have repeatedly had occasion to quote from Tycho's 
letters. Both before and after he had become settled at 
Hveen, to all appearance for life, he kept up a correspon- 
dence with friends at home and with scientific colleag'ues 
abroad. Of the former, only Vedel and Dancey were left, 
and with these he occasionally exchanged friendly letters,^ 
but between him and the acquaintances he had made on 
his foreign travels very lengthy epistles passed as often as 
an opportunity offered of sending these by a carrier, mer- 
chant, or by some casual traveller. Among Tycho's prin- 
cipal foreign correspondents were Paul Hainzel and Johannes 
Major at Augsburg, Scultetus at Leipzig, the Emperor's 
physician, Ilagecius, at Prague, and Brucffius at Rostock. 
Being always anxious to increase his library, Tycho in many 
of his letters inquires about new books, or asks his friends 
to procure them for him, especially such as were about the 
new star or the recent comets. These comets had also been 
observed by Hagecius, and Tycho pointed out the erroneous 
result his correspondent had come to in giving the comet of 
1577 a parallax of five degrees, which would place it far 
within the sphere of the moon, whereas the observations 
made at Hveen showed that the horizontal parallax was less 

^ Epist, p. 162. See also an article, "T. Brahe als Homonpath," by 
Olbers, in Schumacher's Jahrfmch fur 1836, p. 98. Olbers remarks that of 
cimrse Tycho Brahe had too much common sense to believe in infinitesimal 

^ It is characteristic that while Tycho in his letters to Vedel generally 
sends his regards to Vedel's wife, neither of them ever alludes to the mother 
of Tycho's children. Dancey died in 1589 ; he had first been sent to Den- 
mark by Henry II., and came afterwards again when King Frederick II. was 
negotiating to recover the Orkney Isles from Scotland. Owing to the dis- 
turbed state of France, his salary was often considerably in arrear, which 
placed him in a very humiliating position both to the Danish king and to 
private people who had lent him money. Notwithstanding his troubles, 
Dancey was greatly liked and respected in Denmark. 


than a third of a degree.^ Tycho also told Hagecius of tbe 
corrections to the elements of the solar orbit of Copernicus, 
which his own observations indicated ; but neither to the 
Bohemian physician nor to his other correspondents did he 
allude to the new system of the world which he had con- 
structed, possibly because (as he wrote to Hagecius) Wit- 
tich's conduct had given him a lesson which he should not 
forget.^ As Tycho had understood from Wittich that Hage- 
cius had lost his post in the Emperor's household, he invited 
him to come to Denmark, where he might be sure of being 
well remunerated by the king and the nobility for his ser- 
vices as a physician ; but Hagecius declined to leave Prague, 
as he had not lost his post, and found it too risky for a man 
who was no longer young and had a family to settle abroad.' 
With Johannes Major, Tycho corresponded about the Gre- 
gorian reform of the calendar, which was promulgated in 
1582, and ordered to be adopted by the Catholic world under 
threat of excommunication. In consequence of this, Pro- 
testants refused to make any alteration in the calendar. At 
Augsburg several members of the civic council had voted 
against the adoption of the new calendar for theological 
reasons, and when the mayor, in consequence, tried to arrest 
and carry off the principal theologian of Augsburg, the popu- 
lation rose in arms and set him free. When asked for his 
opinion, Tycho very sensibly remarks that if the Pope at the 
time of Regiomontanus (i.e., before the Keformation) had 
improved the calendar, Luther would most assuredly not 
have wished to interfere with it, as this matter had nothing 
to do with religious doctrines ; and why should not the 
new calendar, approved of by the Emperor, be accepted, as 
the Nicean calendar-rules were still accepted even by Pro- 
testants ? Of Tycho's letters to his old fellow-student at 

' T. B. el ad eum Doct. Vir. Episi., pp. 55, 60, and 62. 

' lUid., p. 59. 3 Ibid., pp. 56, 65, and 68. 


Leipzig, Scultetus, five are preserved, although of these but 
three are printed in accessible places;^ one of these '(of 
1 581) deals chiefly with the comet of 1577, for which 
Scultetus also imagined that he had found a parallax ; 
another (of I 592) is written in a jovial manner, Tycho pro- 
mising to drink his friend's health that evening, and expect- 
ing him to return the compliment. Another former Univer- 
sity acquaintance with whom Tycho occasionally exchanged 
letters was Professor Brucasus, who had been appointed to 
a chair of medicine in the University of Eostock in 1567 
while Tycho was studying there. He was one of the com- 
paratively few learned men of the time who would have 
nothing to do with astrology, and it is therefore not to be 
wondered at that he expressed his disapproval on hearing 
about the intended printing of an astrological calendar by 
Elias Olsen at Hveen. He wrote, for instance, that weather 
predictions reminded him of Cato's saying of the Eoman 
haruspices, that he wondered if they could keep from laugh- 
ing whenever they met each other. ^ But though adverse to 
astrology, Brucseus had no objection to an astronomer dab- 
bling in medicine, and in one of his letters he asked Tycho 
to let him know if he was in possession of any remedy 
against epilepsy. They also corresponded on astronomical 
matters, and Tycho pointed out to him the difficulty in 
accepting the theory of Copernicus, and commented on the 
errors of the Alphonsine and Prutenic tables.^ 

Of far greater importance than the above correspondence 

' The first one in T. B. et Doct. Vir. Epist., p. 57 ; the second in Kiistner's 
Geschichte dcr Matkematik, ii. p. 409. The source of both is Singidaria Mis- 
tor ico-literaria Lusatica odcr historisehe und gelehrte Merckimrdigkeiten von 
Ober- und Xieder-Lausltz, 27te Sammlung, 1743, pp. 178 et seq., where there 
are two more letters printed. Scultetus (Schultz) died in 1614 as burgomaster 
at Gorlitz. A letter dated January 1600 is printed in Jl«s T. Brakes Brief - 
uechsel, von F. Burckhardt. Basel, 1887. 

= T. B. ct Doct. Yir. Epist., p. 93. 

* Ibid., p. 75 et seq. 


were the letters exchanged between Tycho and Landgrave 
Wilhelm of Hesse, and his astronomer Christopher Eoth- 
mann. We have seen how Tycho's visit to Cassel in the 
year 1575 seems to have given a fresh impetus to the 
scientific tastes of the Landgrave, who in 1577 engaged 
Christopher Eothmann of Anhalt as his mathematicus, a man 
not without some knowledge of astronomy and mathematics, 
though not possessing the genius of the man who, two years 
later, was engaged as his assistant.^ Joost Biirgi was bom 
in 1552, at Lichtensteig, in the county of Toggenburg, in 
Switzerland, and seems to have been a watchmaker in his 
youth, but nothing is known of his life until Landgrave 
Wilhelm, in 1579, appointed him court- watchmaker at 
Cassel. The methods of observing adopted in the observa- 
tory at Cassel rendered good clocks indispensable, and both 
these and the constantly improved instruments made the 
services of the ingenious mechanician most valuable to the 
Landgrave, who, indeed, was well aware what a treasure he 
had found, as he in one of his letters to Tycho calls Biirgi 
a second Archimedes. Observations were regularly made 
at Cassel by Rothmann and Biirgi, especially of the fixed 
stars, with the object of constructing a new star-catalogue, 
but other celestial phenomena were not altogether neglected, 
and the comet of 1585 gave rise to a correspondence 
between Tycho and the Landgrave. They had lost sight 
of each other since 1575, but the Landgrave was well 
aware that a magnificent observatory had been erected at 
Hveen, and that work was steadily carried on there, parti- 
cularly since the visit of Wittich had put him in possession 
of the important improvements which Tycho had introduced 
in the construction of instruments. He was therefore 

1 Neither the year of Rothnnanu's birth nor that of his death are known. 
About him and BUrgi, see in particular Rudolph Wolf's Geschichte der Astro- 
nomic and his Astronomische Mittheilungen, Nos. 31, 32, and 45. 


aimoiis to leam what obseiratioiis Tvcho had made oi :h- 
comet of 1 5 S 5 . as it was not a reiy conspicnc- s one. r^d 
prC'bably woTiId not b? cbserved bv manv astroncniers. 
With this xiew the landgraTe wrote a letter to the learned 
Heintich Ea^tzc-r. goremor cf Hc'stein.- asTring tlat hi; 
coitipliiaents mig-it be sent to Tyclio. with a tint that he 
would be glad to hear societhiag of the cbserratio'iis of this 
ccimet nadd at Hveen. Tvcho was very tappy to renew 
Ms acqaaintance with the LandgTare. to whom he wrote a 
long letter on the 1st of IMarch 15S6. ia which he enclosed 
an abstract of his observations of the comet. In the letter 
he sngg-ested an exchange of C'bservaticns of the star of 
I 57 J and of the recent comets, claimed the initmmental 
impK'vements alreadv annonnced to the Landgrare as his 
own, and gave an acconnt of varicns instmments he had 
designed, snch as a bifnrcated sextant, to be nsed by twj 
observers, and the equatorial armilUe. He pointed out the 
great convenience of the latter instrument, which directly 
gave the right ascension and declinaticn of an ob^'ect. frC'm 
which the lonaitnde and latitude could be fcnnd either by 
calcnlation, or by a specially prepared table, or by a large 
globe. Tvcho als-:) sent the Landsrave a solar ephemeris 
for the cttrrent vear. and asked him to compare his cbser- 
vations with it. This letter and its appendices w^ere sent 
to Cassel by Tycho's assistant. Flemlvse, who was bonnd 
for tie book-mart at Frankfcirt, and ccnld take Cassel on 
his wav. where Tvcho donbtless also wished him carefclly 
to inspect the improved instrnments. 

To this letter the Landgrave at once replied, and Eoth- 
mann also took the opp-ortanity of entenng into corre- 
spondence wirh Tvcho. During the next six years letters 

* Bantzov '1526-1:031 was Crlrbratei as a c.'.'.iczc'T. n:" only cf br-ks (of 
which ce r->?=^ss€d abtTi: ~zcc voltunesl. c-t a'.s^"- cf w..r:i= cf ^z^ He &_=-:> 
WTi'fcr on a.-TToI : jv. 


continued to be sent backwards and forwards between 
Cassel and Uraniborg, in whicli were discussed the metiiods 
of observing, the instruments in use, and, after the publi- 
cation of Tycho's system of the world, also the question 
whether this system or that of Copernicus was the true one. 
We shall in the sequel have many opportunities of quot- 
ing these letters, or rather astronomical essays, of which 
Tycho recognised the interest to the scientific world by 
sending copies of some of them to several other correspon- 
dents, and finally by publishing them all in a volume 
printed at Uraniborg, which forms an excellent supple- 
ment to his other writings, and completes the picture of 
his scientific activity.'' 

All the details about Tycho's observatory which the 
Landgrave had learned from Tycho's letters to himself and 
Ruthmann had naturally made him anxious to see it for 
himself, and an opportunity of doing so seemed to offer itself 
in 1588, as there was to be a meeting of North German 
princes at Hamburg, which the Landgrave was going to 
attend. King Frederick had already given orders to have 
ships ready to carry the Landgrave over to Seeland, when 
the king's death prevented the meeting at Hamburg, and 
with it a second meeting of Tycho and the Landgrave.^ 

But though Wilhelm IV. never came to Hveen, Tycho 
had from time to time the pleasure of welcoming other 
distinguished guests at Uraniborg. Among these we shall 
here mention Johan Seccerwitz, professor in Greifswalde, 
who is known as a Latin poet. He came to Denmark in 
I 580 with the Duke of Pomerania to attend the christening 

^ A short chronological summary of the principal points of interest in this 
correspondence is given by Delambre in his Ilistoire de V Astronomic Moderne, 
torn. i. pp. 232 et. seq. See also Gassendi, p. 65 et scq, 

^ Epist. Astron., in the dedication to the Landgrave's son, and also p. 104, 
The " Oomitia Hamburgensia " was, I suppose, a meeting of the princes of 
the Nether-Saxon circle, to which King Frederick belonged as Duke of 


of a new-born princess, and met Tyclio in the house of the 
Bishop of Lund. He has left a versified description of liis 
journey, in which he expresses his joy at having made the 
acquaintance of Tycho. In 1584 the French historian 
Jacques Bongars was at Uraniborg.-"^ Another learned visitor 
was Duncan Liddel, who was born at Aberdeen in 1561, 
and had studied at Frankfurt-on-the-Oder and at Breslau. 
la 1587 te went to Rostock, and while studying there 
paid a visit to BEveen on the 24th June.^ He was professor 
at Helmstadt from 1591 to 1607, and is said to have been 
the first person in Germany who explained the motions of 
the heavenly bodies according to the three systems of 
Ptolemy, Copernicus, and Tycho.^ Some travellers who 
were not of a scientific turn of mind were nevertheless 
attracted to Hveen by the wonderful things to be seen there. 
Thus, in 1582 Lord "Willoughby d'Eresby, who had been 
sent by Queen Elizabeth to invest King Frederick with the 
Order of the Garter, paid a visit to Uraniborg, and brought 
with him a physician, Thomas Mufiet, in whom Tycho was 
pleased to find an acquaintance of his friend Hagecius.* 
Daniel Eogers, who was on several occasions employed by 
Queen Elizabeth on missions to the Netherlands and Den- 
mark, was also acquainted with Tycho, and in 1588, when 
he came to condole on the king's death, he went to Hveen, 
where he promised Tycho to obtain for him the copyright 
of his books in England.^ Below we shall see that Tvcho 

' Danske Magazin, ii. pp. 210 and 220 CWeistritz, ii. pp. 105 aud 126). 
- Mcteorol, Diary. 

* About Liddel, see above p. 121, footnote. He died at Aberdeen in 1617. 

* Letter to Hagecins, T. B. et Doct. Vii: Epist., p. 70. Tycho does not 
mention that Lord Willoughby had landed at Elsinore on the 22nd July, but 
that the king's installation as a K.G. did not take place till the 19th August, 
because the king for a long time refused to be dressed in the full costume, &c., 
in public. Dancey had to assist in settling the matter. 

^ Tycho tells this in a letter to Peucer, and adds that he had already secured 
the copyright in Trance and Germany (Weistritz, i. p. 264). Rogers {1540- 
1550) was a man of considerable learning, particularly in British antiquities; 


was to receive even more exalted visitors from abroad durinc 


the last years of his residence at Hveen. 

It is needless to say that Danish visitors frequently 
crossed over the Sound to the little island which had so 
suddenly become famous. Both learned and unlearned men 
were ready to pay court to the great astronomer who had 
raised a beautiful building full of curious apparatus on the 
lonely island. Though this spot had expressly been selected 
for his residence in order that Tycho might undisturbedly 
devote himself to the studies he loved, he had probably no 
objection now and then to receive as his guests even some 
of those who had in former days sneered at his scientific 
tastes/ and not a few among the Danish visitors were men 
of learning. Among those who paid repeated visits was 
Tycho's former tutor and his friend through life, Anders 
Sorensen Vedel, who was now royal historiographer, and 
lived at Elbe in Jutland, as a canon of the cathedral there. 
He was on a tour through Denmark to collect topographical 
and other information for his Danish history, when he 
arrived at Hveen on the 13th June 1586. He must have 
stayed there some weeks, as he was still with Tycho when 
a stately little fleet on the 27th June approached the island 
from Seeland with Queen Sophia on board. The queen was 
a daughter of Duke Ulrich of Mecklenburg- Giistrow, and was 
an able and accomplished lady. Tycho's mother, Beate Bille, 
acted as her Mistress of the Robes (to which post she was 
regularly appointed in 1592 after the death of his aunt 
and foster-mother, Inger Oxe), and the queen was therefore 
interested beforehand in Tycho and his work. She was 

he had studied at Wittenberg during the persecution of the Protestants by 
Queen Mary. Perhaps he is alluded to in the Meteorol. Diary, 9th July 1588, 
" Angli aderant." 

^ Fortunately for him, Tycho lived before the age of telescopes, so he was 
not annoyed by constant requests " to see the moon " or to " take an observa- 
tion through the big telescope." 


detained on the island by a storm till the 29th, so that she 
had time enough to see everything of interest, and to con- 
verse with Tycho and Yedel on the various topics which 
the scenery of the island and the curiosities of the obser- 
vatory and laboratory suggested. At table Tycho called 
the queen's attention to Vedel's historical researches and 
his collections of ancient ballads and other folk-lore, a sub- 
ject in which she took a great interest. She asked Vedel 
for a copy of these ballads or Kjcempeviser, which he pro- 
mised to send as soon as he could, and this incident gave 
rise to Yedel's collection of ancient ballads being printed 
five years later.'' The queen must have enjoyed herself 
well (she is said to have had a taste for chemistry), and 
two months afterwards, on the 23rd August, she brought 
her father and mother ^ and a cousin to see Uraniborg, 
and was on this occasion attended by a large suite. The 
Duke was also fond of chemistry, which in those days was 
a fashionable occupation, owing to the prevailing opinion 
that it would sooner or later lead to the discovery of the art 
of making gold.^ 

King Frederick did not accompany the queen on either 
of these occasions, and it is not certain that he ever was at 
Hveen.* In contemporary documents and in Tycho's own 
writings there is no allusion to the king's having visited 

^ Wegener's Life of Vedel, p. 148. The reader may recollect that Vedel's 
edition of the Kjcempeviser is referred to in Note K. to " The Lady of the 
Lake." The queen wrote somewhere at Uraniborg her motto " Gott veriest 
die Seinen nicht." 

^ Elizabeth, daughter of King Frederick I. of Denmark. 

^ Tycho told the Landgrave about this visit in a letter dated 1 8th January 
1587 {Epist. Astron., p. 36). In March 1592 the queen wrote to T. Brahe 
requesting him to send her father a small barrel of emery, as the Duke had 
heard that some had lately been found at Hveen, and for herself she wanted 
some " burnt antimony," such as she had got from him before. Friis, Breve 
og AUstykker angaaende T. Brahe. Copenhagen, 1875, p. 5. 

■■ The king was in Jutland and North Slesvig during the last days of June 
(Wegener's Life of Vedel, p. 149), and that he did not accompany the queen 
in August is evident from Tycho's letter to the Landgrave just quoted. 


liim, and if he had done so during the last three years 
of his life, it would certainly have been mentioned in the 
meteorological diary, in which during this period all events 
of that character were noted.'^ But this does not exclude 
a visit of the king to Hveen before 1585, and it would 
indeed be strange if he had never during the years he was 
building the castle of Kronborg at Elsinore, with the island 
before his eyes, crossed over the narrow strip of water to 
see the buildings of which he must have heard so much, 
and to whose owner he continued to show favour on every 
occasion. The king might also have taken the opportunity 
of seeing Uraniborg in the year 1584, when his eldest son, 
Prince Christian, was elected his successor. On the 20th 
July the nobility of Scania swore fealty to the prince at 
Lund, where Tycho Brahe also appeared among the other 
nobles of the province, and the king was apparently in 
Scania at that time. A remarkable document, which is 
still in existence, and is printed among the many important 
letters in the Danshe Magazin,^ seems to show that the king 
was expected at Hveen at that time. It is a draught of an 
act, written in Latin and in the king's name, dated " Huenee 
in Avtopoli Vranopyrgensi," the ist July 1584. In this 
document the king, in recognition of Tycho Brahe's scientific 
work, and following the memorable examples of former ages, 
grants to him and his heirs male for ever the island of 
Hveen in fief, with all privileges and honours, provided that 
they do nothing to injure the king or kingdom, and keep 
the buUdings of the island solely for the furtherance of 
mathematical studies. But this document was never en- 
grossed and signed by the king, and even if Tycho could 
have persuaded the king to grant him so great a favour, it 

^ It is curious that the very first note of an historical character is under 
the 27th April 1585 : "Nuncium de adventu Regis," but in the following 
there is nothing about him. 

' ii. pp. 220-221 (Weistritz, ii. p. 124). 


would have been very hard for the king to obtain the con- 
sent of the Privy Council, although its principal members 
were at that time very friendly disposed to Tycho ; and in 
particular these great nobles would have protested against 
so monstrous a proceeding as the transmission of a valuable 
fief to the children of a " bondwoman." Probably the act 
was only drawn up in an idle moment, while the writer ^ was 
thinking about the chance of a visit from the king, but it 
shows at any rate that Tycho's wishes went in the direction 
indicated by the draught, and that he felt the insecure 
position in which all his creations at Hveen were placed. 
All his endowments were only enjoyed by him during the 
king's pleasure, and even the island was only granted for 
his own lifetime. Were then the beautiful buildings and 
wonderful instruments some day to vanish again, as the 
observatories of Alexandria, Cairo, Meragah, Cordova, and 
Nilrnberg had vanished ? This thought was doubtless a 
painful one to Tycho, who, the more he studied the stars in 
the heavens and the elements in the earth, could not but 
feel that life was short and art was long. 

While his royal protector lived, Tycho and his observa- 
tory were, however, safe enough ; that much he knew, not 
only by the readiness with which one pecuniary grant after 
another was made to him, but also by many more private 
acts of kindness and good feeling which emanated from the 
king, and of which we have ample proofs in various letters 
still extant. The king evidently looked on Tycho not only 
as a great man, whose achievements conferred honour on 
the country and on the monarch who supported him, but 
also as a confidential servant to whom he could turn for 
advice on matters within his province, and whom he in 
return delighted to honour and befriend. All the existing 

^ According to Friis (Elias Olsen Morsing, Copenhagen, 1S89, p. 6), the 
handwriting seems to be Vedel's. 


portraits of Tycho Brahe represent him as wearing round 
his neck a double gold chain, by which is suspended an 
elephant. It is not known on what occasion the king pre- 
sented him with this mark of favour, but the source whence 
it came is evident from the king's initials, motto, or minia- 
ture, which on different portraits are shown on the elephant.' 
But in addition to this more ornamental than useful present, 
the king frequently bestowed others of a more practical 
nature on Tycho. Thus he sent in June i 5 8 1 an order to 
the treasury to pay the cost of a bell which had just been 
cast at Copenhagen for Tycho, and which was to be used at 
Hveen. Perhaps it was this bell which was suspended in 
the cupola at Uraniborg. Again, in November 1583 the 
king ordered the treasury to hand over to Tycho " a good 
new ship or pilot-boat," with all necessary tackle, &c.^ 

From some letters of the king's it appears that Tycho 
entertained plans of some work of a geographical and his- 
torical character, for in September 1585 the king instructed 
his librarian to lend to Tycho Brahe " as many chartas 
cosmographicas or maps as are to be found in our library at 
our castle of Copenhagen, and which are of our kingdom, 
Denmark, or Norway, or any other of our dominions, for 
information in some undertaking of which he has told us."^ 
A few weeks later the governor of Kronborg Castle was 
iuformed that whereas Tycho Brahe had stated his intention 
of publishing something about Danish kings, and had re- 

^ On the contemporary painting, which was destroyed in the burning of 
Frederiksborg Castle in 1859, (of which there is a copy in Friis's book), asmall 
miniature is seen on the middle of the elephant. The engraving, which occurs 
in several of Tycho's printed works {by Geyn, dated 1586), shows on the 
elephant the letters F. S. (Fredericus Secundus), while the portrait of 1597 
(copied in this book) has the miniature, and underneath the elephant the 
letters M. H. Z. G. A. (Meine Hoffnung zu Gott allein), the king's motto. 

^ Dansie Matjazin, ii. p. 217 (Weistritz, ii. p. Ii8). 

^ Ibid., ii. p. 219 (Weistritz, ii. p. 121). 

■* Werlauff, SistorisJce Efterretninger om del Store Kongelige Bihliotkek. 
Copenhagen, 1844, p. 9. 


quested that he might get their portraits as shown ou the 
new tapestries at Kronborg, the king's painter was to be 
ordered to copy all the portraits and Danish and German 
rhymes on the tapestries.^ Possibly Tycho may have wished 
to find some work for his newly-acquired printing-ofSce, but 
if he really intended preparing a work on the geography 
and history of Denmark, he never carried out this plan. It 
seems, however, more probable that he had intended to assist 
his friend Vedel, who just at that time was collecting materials 
of this kind in connection with the work on Danish history 
on which he was engaged. 

In return for all the kindness shown by the king, Tycho 
from time to time rendered such service to his patron as 
he was able to offer. Thus his name is associated with the 
castle of Kronborg by a couple of Latin poems with which 
he ornamented this favourite building of the king. On 
one of the gables was placed a lengthy versified inscription 
praying for a long life and success to the builder and his 
work ; on the dial of a clock in one of the towers he put 
these lines : 

" Transvolat hora levis nec[iTe scit fugitiva reverti, 
Nostra simul properans vita caduca fugit." ^ 

Tycho was scarcely settled at Uraniborg before the king 
wished to consult; him. In September 1578 he wrote to 
the astronomer from Skanderborg, in Jutland, that it was 
said by the common people about that place that a new star 

^ Visitors to Copenhagen may still see some of these tapestries in the upper 
storey of the Museum of Northern Antiquities. They were made between 1 58 1 
and 1584 from designs by Hans Knieper of Antwerp, whom we have men- 
tioned above as having painted part of the picture on Tycho's mural quadrant. 
The tapestries (which originally numbered III) represent each a Danish king 
in full figure, with the name and a short account of his reign in German 
rhymes above. 

- Pontoppidan's Bamke AUas, torn. ii. (1764), p. 272 et seq. A poem with 
which Tycho ornamented one of the clocks in the study at Stjemeborg is 
printed in Epist. Astron., p. 245. 


liad again appeared in the heavens, and he therefore asked 
what planet or other star might have been mistaken for a 
new star.^ Again, in December 1584 the king turned to 
Tycho for help, writing that he was under the impression 
that he had returned to Tycho a compass made by the 
latter, as there was something wrong with it. If this was 
the case, Tycho was to send back the compass ; but if not, 
he was to make two new ones similar to the old one.^ 

But the most important service (according to the ideas 
of the time) which Tycho had to render to the king was 
by astrological predictions. The first occasion on which he 
was ordered to show his skill in such matters was probably 
in 1577, when the king's eldest son. Prince Christian, was 
bom. The king and queen had been married since 1572, 
and two daughters had been bom of the marriage, when at 
last a son was bom at Frederiksborg Castle at half-past four 
o'clock in the afternoon on the i 2th April I 577. Popular 
tradition has preserved several strange circumstances in 
connection with the birth of this prince, who afterwards 
became one of the most popular kings of Denmark. An 
old peasant announced to the king in the previous autumn 
that a mermaid had appeared to him and commanded him 
to tell the king that the queen was to be delivered of. a 
son who should be counted among the most renowned 
princes in the northern countries. The infant prince was 
christened on Trinity Sunday, the 2nd June, at Copenhagen, 
with the solemnities and festivities usual on such occasions, 
and among those who attended the ceremony and had an 
opportunity on the two following days of being edified by 
the stories of the virtuous Susanna and David and Goliath, 
which the students of the nniver.sity acted in the courtyard 
of the castle, was Tycho Brahe, to whom doubtless more 

' Darwke ifo/jozin, ii. p. 204 (Weietritz, ii. p. 93). 
2 Friis, Tyje Bratte, p. 147. 


tlma one eye was directed wlien hopes and wislies were 
uttered for the future of tlie little prince. In those days, 
when most people of note had their nativities worked out 
for them, it must have been a comfort to the king that he 
could get this done for the infant by so great an authority 
as his renowned star-gazer was already considered. Tycho 
Brahe was accordingly directed to prepare the horoscope of 
the prince, and on the 1st July following he handed in a 
detailed report of his investigations. The original document 
does not appear to have been preserved, but there are two 
copies (apparently of a somewhat later date) in the Eoyal 
Library at Copenhagen.^ The report contains, first, a dedi- 
cation to the young prince, after which follow the calculation 
of the requisite astronomical data and the discussion of the 
astrological signification of these, all written in Latin, but 
followed at the end by a German translation of the astro- 
logical predictions, probably prepared for the convenience 
of the queen. The dedication alludes shortly to the origin 
and importance of astrology, and uses the same arguments 
as we have met with in Tycho's oration on this subject. 
The positions of the planets are next calculated for the date 
of the prince's birth by the Prutenic tables (the successive 
steps being given for each planet), while those resulting from 
the Alphonsine tables are also given, but merely for the 
sake of comparison. Being a practical astronomer, the 
writer was not content with this, but corrected by means 
of his own observations the tabular places of Jupiter, Mars, 
Venus, and the sun, adopting the positions of the other 
planets as given in the Prutenic tables because he had no 

1 " Horoscopns Sr. Regis Christiani ITti., ad Mandatum Sr. Regis Fride- 
rici Ildi., a Tychone Brahe Ottonide conscript, in Insula Hvena Cal. Julij 
Ao. 1577." The two copies must be of slightly later date, as the prince did 
not become king till 158S. The dedication is to " Incljto et Uliistri Infant! 
Christiano, Opt. et Potentiss. Principis Priderici Ildi. Dauise et Norvegiee 
Regis, Domini Clementissimi Pilio primogenito." 



recent observations of them. The figura nafalis is not of 
tlie square shape generally used by astrologers/ but circular, 
in accordance with the plan already followed by Tycho in 
the case of the new star. 

Before giving a short account of the further contents of 
Tycho's report on the horoscope of Prince Christian, it may 
not be useless to say a few words about the general prin- 
ciples followed by astrologers in preparing horoscopes ; re- 
ferring for further particulars to works in which this subject 
is treated in detail.^ 

The point of the heavens of greatest importance for the 
fate of man was the point of the ecliptic which was rising at 
the precise moment of his birth (pundum ascendens). The 
next step for the astrologer was to see how the planets 
and the signs of the zodiac, as well as a few of the most 
important fixed stars, were at the same moment situated in 
the twelve " houses " into which the heavens were divided.' 
The first house, ascendens or Jwroscopus, was considered the 
foundation of fate, and if Mercury or a favourable star was 
found in this house, it would announce a happy and pros- 
perous life, while, on the other hand, an unfavourable planet 
(Saturn or Mars) would indicate a short and unhappy life. 
The second house (north of the first one) gave information 
about riches and possessions ; it was an unlucky house, be- 

^ See, e.g., Walleustein's and Kepler's horoscopes in Kepler's Opa-a Omnia 
vol. i. p. 293, and vol. v. p. 476. 

- See, in particular, Origaai Novce Calestiwm Motuum Ephemerides, Frank- 
furt, 1609, vol. i. ; or of modern books, MaxUhlemann, Grundziige der Astro- 
nomic und Aslrologie der Alien, hesonders der uEgypter, Leipzig, 1857 ; Kepler's 
Opera Omnia, ed. Frisch, i. p. 293 ; Delambre, Hist, de I'Astr. Anc, ii. p. 546 ; 
Moyen Age, p. 290 and p. 496 et seq. 

^ As already remarked, different astrologers divided the heavens in different 
ways (Delambre, M. A., p. 496 et seq,), by dividing the zodiac or the equator 
by circles through their poles, or (as Tycho did) by circles through the north, 
south, east, and west points of the horizon. About the Babylonian origin of 
these " houses," see Mr. G. Berlin's lectures on Babylonian Astronomy in 
Nature, vol. xl. p. 237. 


cause it was not in favourable aspect to tlie first one, and 
while a favourable star (Jupiter or Venus) would here point 
to great riches, a questionable character like Mercury might 
make a thief and a vagabond of the new-born infant. 
Similarly the other houses had each a separate significa- 
tion ; the third refers to brothers, friends, or journeys ; the 
fourth, or most northern house (imum ccelum), refers to 
parents, because it is in quadrature with the first house, and 
therefore closely allied to it ; the fifth (iona fortuna) tells 
about children, and is a very favourable house, because it is 
in aspedus trigonus with the first one, and Venus placed 
here would have great effect. The sixth house is a bad one 
(mala fortuna), because it has no aspect to the first, and, 
perhaps on this account, is allotted to servants, health, 
women, &c. The seventh and easternmost house, opposite 
the first, refers to marriage ; the eighth is a bad one (no 
aspect) and refers to death, and here only the moon is 
favourable. The ninth house is intimately connected with 
the first (aspedus trigonus), and the sun is here of particular 
value ; this house deals with religion and journeys. The 
tenth house (medium crnli) gives information about life, 
deeds, country, residence, &c. The eleventh (bonus dmmon), 
is in aspectus sextilis with the first, and is generally speaking 
a favourable house ; but at a birth in the night, Saturn 
would here cause cowardice and poverty, and for a person 
born in the daytime. Mars would here induce loss of 
property. The twelfth house is, like the second, a bad one 
(malus dmmxin), and tells of enemies and illnesses. Having 
drawn all these " houses " on a diagram and inserted the 
planets in them, the astrologer proceeded to examine the 
aspects of the latter (conjunction, opposition, quadrature, 
&c}), and make out the prognosticum by means of rules, as 

' Of these conjunction, aspectus trigonus and sextilis were favourable, 
opposition and quadrature unfavourable. 


to wliich much difference of opinion existed. Some of the 
most important things, however, were the directions. So- 
called circles of position were drawn through the north and 
south points of the horizon and any two points of the zodiac, 
called the significator and the promissor (the sun, moon, 
or planets, according as they had to be considered), and 
the arc of the equator included between these circles was 
their directio} Thus Tycho computes the direction of the 
ascendant to the planets (remarking that an error of four 
minutes in the stated time of birth will alter these direc- 
tions by one degree, which corresponds to an error of one 
year in the time of any event foretold by a direction), and 
also the directions of sun, moon, and Venus to the other 
planets. There were various methods of " directing " or 
referring the effects of the planets, as they might be placed 
at any subsequent time, to their positions at the moment 
of birth. Thus Kepler says that if the sun at this moment 
be in a certain place in the zodiac, and a planet afterwards 
comes to an important place, it should be computed how 
many days after the birth the sun took to reach that place, 
and the number of days corresponds to the number of 
years which will elapse from the birth before the power of 
that configuration will be felt.^ 

The action of each planet was very different according to 
the house and sign of the zodiac which it occupied. The 
sun and moon had each a sign (by some also called house) 
specially belonging to it (Leo and Cancer), and the other 
planets had each two, and a planet exercised the greatest 
power when it was in its own house. The sun and moon 
are the most powerful, while the others have the greater 
effect the nearer they are to one of those. If a planet is 

^ Directions might also be taken along the ecliptic. See, e.g., some remarks 
on this matter in a letter from Tjoho Brahe to Ludolf Ridderahusen of 
Bremen, of April 1600, in Breve og AhtstykTcer (1875), P- 121. 

2 Kepleri Opera, i. p. 295. 


not in its own sign, but in that of another planet, the two 
bodies act together, either with increased effect if they are 
of the same nature {e..g., both favourable), or neutralising 
each other more or less if of opposite nature. 

After this necessarily very crude outline of the principles 
of judicial astrology, we return to Tycho's forecast of the 
fate of the new-born prince. It would, however, lead us 
too far if we were to follow him through the various proofs 
which he adduces for his statements, and we can only 
mention some of the more important ones. The years ot 
infancy will pass without danger, as Venus is favourably 
placed in the ninth house, and though in the second year 
the opposition of Mercury to the ascending point indicates 
some small illness, it will be nothing serious. The years of 
the prince's life are then enumerated in which he will be 
afflicted with illness. For instance, in his twelfth year the 
ascendant will be in quadrature with Saturn, which indicates 
some serious illness " arising from black bile," but it will 
not be mortal. In his twenty-ninth year he will have to 
be very careful both about his health and his dignity, 
because the sun will be in quadrature with Saturn at the 
same time as Venus and the latter are in opposition. A 
very critical time will be about the fifty-sixth year, when 
the sun and Mars are most unfavourable, and even Venus 
cannot help, as she is in the eighth house. The methods of 
the Arabians do not show any life beyond fifty-six years, 
and Ptolemy's rule gives the same result. As the sun's direc- 
tion to its setting gives 41^ years,'' the moon, Venus, and 
Jupiter add together twenty-six years, and Saturn in quad- 
rature subtracts lof, so that the result is about 56-^ years. 
As there are so many concurring signs, the prince will 

^ This is easy enough to understand. On the 1 2th April the sun would 
set about 7h. 17m. or 2h. 47m. after the prince's birth. As four minutes or 
one degree corresponds to a year, 2h. 47m. is not quite forty-two years. 


hardly survive that age, unless God, who alone has power 
over human destiny, specially prolongs his life ; and if the 
prince gets over the critical period, he will have a happy 
old age. Passing to the question as to what planets are the 
ruling ones, it appears that Venus is ruler of the nativity 
{domimis geniturce), being close to the tenth house or sum- 
7num cceli ; but Mars is in conjunction with Venus, and in 
the sign belonging to Mercury (Gemini), so that these two 
also have great influence. Venus will make him pleasant, 
comely, and voluptuous, fond of music and the fine arts ; 
Mars makes him brave and warlike, while Mercury adds 
cleverness and acuteness to his other faculties. He will be 
of a sanguine temperament, because nearly all the planets 
which indicate the temperament are in sanguine signs, but 
at the same time he will not be without some saturnine 
gravity. Venus, as the ruler, determines his character, and 
as Mars is joined to her, the prince will indulge too much 
in sensual enjoyment, but Mars in the sign of Mercury will 
make him generous and ambitious. He will be healthy 
and not subject to illness, but in various years (which are 
enumerated) he must be careful, as the ascendant will be 
influenced by the malevolent rays of Saturn. His mental 
abilities will be very good, because Mercury is favourably 
situated ; and as this planet is in a good aspect with Venus 
and Mars, the prince will be fond of warlike occupations 
and field sports, and take an interest in surgery and other 
sciences. He will have good luck in his undertakings, as 
Saturn is in the fourth house and in his own sign of Capri- 
corn, while Mercury and Mars occupy each other's signs ; 
but as Jupiter is badly placed, the prince will be less suc- 
cessful in ecclesiastical matters.^ As regards honours and 

^ Probably because Jupiter had an oracle at Dodona, and therefore was of 
a clerical turn of mind. Here he was in the twelfth house and in the sign of 
Mercury (Virgo), both circumstances bad. 


dignities, it is an excellent circumstance that tlie most bril- 
liant of all stars, Alhabor, in the mouth, of Sirius, is in the 
corner of medium colli, and there are also other fixed stars 
of importance in favourable positions, such as the Twins in 
the tenth house, Spica in the first, with Corona borealis a 
little above, and the Southern Crown exactly in the corner 
of the fourth house. Among the planets, the sun has most 
influence on honours and dignities and is well placed, and 
only Saturn in opposition to medium codi shows that the 
prince will meet with some serious adversities, which, how- 
ever, will be overcome as everything else is so favourable. 
The years are mentioned in which he will be specially 
fortunate or unfortunate ; and here again it appears that 
after his fifty-fifth year, " when the direction of the sun 
overtakes Mars," there will be serious adversities awaiting 
him. As to riches, it is especially of importance that pars 
fortunce ■"• is well situated in the eleventh house, and the 
sun is in the seventh, and the prince will therefore become 
rich ; but as the sign of Mars {Scorpio) is in the second house 
{domus divitiarum), his riches will principally be acquired 
by war. At great length it is set forth in which years of 
his life the position of pars fortunce with regard to the 
planets portends the acquisition of riches. The prospects 
with regard to marriage are not altogether favourable, as 
the moon is in the sixth house, and the position of Venus 
with regard to Mars and Saturn signifies some adversity 
in matrimony ; but, on the other hand, Mercury is in the 
seventh house (domus conjugii), which promises some hap- 
piness. Tycho here adds the remark, that in his opinion 
the prince will be more inclined to other amours than to 
matrimony (which turned out true enough). The time when 
he will be inclined to marry will be about the age of twenty 

^ Pars fortwncB is the difference of longitude between sun and moon added 
to the longitude of the pimctum ascendens; it is indicated by the sign ©. 


or twenty-one, when Venus comes in sextile aspect with 
Jupiter about the medium cceli, or in his thirty-fourth or 
thirty-fifth year, or, if not married before, in his forty-seventh 
year, when the moon reaches the seventh house. But all 
this depends more on man's free will than on the stars. It 
does not seem that he will have many children, as Saturn 
is master of the fifth house, and is in a sterile sign, but if 
he has any, they will be healthy and long-lived. His friends 
will be " solar people," such as kings and princes, because 
the sun is ruler of the eleventh house, where _23ars fortunce 
is placed. His enemies will be "jovial and mercurial 
people," because Jupiter is unluckily placed in the twelfth 
house, and Mercury ruling the twelfth is in the seventh, but 
the latter planet assumes the nature of Mars, which is in its 
sign. His enemies will, therefore, be ecclesiastics and war- 
riors, but he will defeat them, because Venus, the ruling 
planet, is much higher in the sky than Mars, and is in the 
apogee of its excentric ; but he must beware of captivity or 
exile on account of the position of Mercury, which is also 
injured by being in quadrature with Saturn. There is 
nothing to indicate a violent death, and the prince will die 
from natural causes, but Venus shows that he will cause his 
own death by immoderate sensuality. 

Finally, Tycho ends this dissertation by saying that all 
this is not irrevocably settled, but may be modified by many 
causes. God is, besides, the origin of all, and the giver of 
life and all good things, and He disposes freely of everything 
according to His own judgment. He alone is therefore to 
be implored that He may rule our life, grant us prosperity, 
and avert evil.''- 

The reader will pardon this long digression, but judicial 
astrology has played so important a part in the history of 

^ " Ille potest Solis currus inhibere volantes, 
Ille augere potest, toUere fata potest." 


the world, and been so beneficial in farthering the study of 
astronomy, that it cannot be left out of consideration if we 
wish to get a full view of the scientific life and doings of 
former ages. Having devoted so much space to the horo- 
scope of the first-born son of the king, we shall not review 
those of the younger sons, which Tycho was afterwards called 
on to prepare, although in these cases the originals (and not 
merely copies) have been preserved in the Royal Library at 
Copenhagen. The second son, Prince Ulrich, was born on 
the 30th December 1578, and Tycho worked out his 
Genethliaca by royal command, and presented it in May 
1579. It is a handsome volume in small 4to, bound in 
pale green velvet with gilt edges, containing about 300 
pages, all written in Tycho Brahe's own hand. The arrange- 
ment of the contents is like that of the previous prognosti- 
cation, the results being, as before, given first in Latin and 
afterwards in German. Mars is the ruler, as he is in his 
own sign, and in every way most favourably situated, but 
the sun is dominus ascendentis, and the solar eclipse of the 
2 1st July 1590 in the eighth degree of Leo, and "in the 
very degree of the ascendant," will be of great importance, 
and may injure the prince. It is again repeatedly pointed 
out how uncertain' the whole thing is.^ In 1583 the king's 
third and last son, Hans, was born on the 26th July, and 
Tycho had again to attack the twelve houses, aspects, &c. 
He sent in a volume like the last one, bound in the same 
manner, and containing about the same number of pages, 
but the Latin part is neatly written by one of Tycho's 
assistants, and only the German part by himself. To show 
his readiness to please the king, he has, in addition to the 
circular figure, divided into " houses " in the same way as on 
the two previous occasions, drawn two square figures, divided 

■* Round the four sides of the central part of the figura natalis Tycho has 
written ; " Potest — fata augere — Deus— toUere fata." 


by distributing the houses evenly round the equator and 
round the ecliptic. In the preface he talks about the possi- 
bility of averting the inclinations of the stars in the same 
strain as before, and throughout the whole dissertation he 
seems more doubtful about the results to be expected than 
he was in 1577. He has again corrected the places of 
the planets by his own observations. Mercury is here the 
strongest planet, free from the rays of the sun, though 
somewhat weakened by being retrograde and moving slowly, 
biit particularly by being in the sixth house. The prince 
seems only to have " mediocre " luck in store, but Tycho 
remarks that everybody shapes his own fortune.^ 

That Tycho did not take much interest in nor attach any 
importance to these astrological prognostications will be 
evident to anybody who has read the foregoing pages. 
Whatever he had thought about these matters in his youth, 
the great work of his life now stood so clearly before him, 
that he did not care to waste his time on work of so very 
doubtful value as astrological forecasts.^ We possess even 
stronger testimony to this effect than any we have yet 
quoted, in a letter which he wrote on the 7 th December 
I 5 87 to Heinrich von Below, a nobleman from Mecklenburg, 
"who in I 5 yg, through the queen's influence, had received 
an estate in Jutland in fief, and who was married to a first 
cousin of Tycho's.^ Duke Ulrich of Mecklenburg-Giistrow, 

^ " Quisque suae fortunse faber : tamennon est dubium astrainhisplurimuin 
posse, ut non immerito dixerit Poeta ille : 

' Esse igitur sapiens et felix nemo potest qui 
Nascitur adverse coelo stellisque sinistris.' " 

- All the same, he was naturally looked upon by the common people in 
Denmark as nothing but an astrologer, and thirty-two unlucky days are 
attributed to his authority (Hofman, Portraits historiques dcs Iwmmes iUustrei 
de Denmark, vi. Partie, p. 23), though nothing could be more opposed to the 
principles of astrology than the fixing upon certain dates as lucky or unlucky. 

^ C. G. F. Lisch, Tycho Brahe und seine Verhdlinisse zu Meklenburg, in 
the Jahrbiioher des Yereins filr MeUenburgische Geschichte, vol. xxxiv. 
(1869). I quote from a reprint, 20 pp. 8vo. See also Note C. 


the queen's father, had. procured two prognostica for the 
year 1588, the one by Tobias Moller, the other by Andreas 
Eosa ; and as they were so far from agreeing, that one let 
the year be governed by the two beneficent planets, while the 
other put it under the dominion of the two malevolent ones, 
the Duke requested Below to inquire from his kinsman Brahe 
which of them was correct. In his answer Tycho remarked that 
he did not care to mix in astrological matters, but for some 
years had endeavoured " to put astronomy into proper order," 
because only in this way, by reliable instruments and mathe- 
matical methods and certainty, could the truth be arrived 
at. He shows that the two prognostics differ so much 
because one is built on the Prutenic, the other on the 
Alphonsine tables, which differ nineteen hours as to the time 
of the vernal equinox. It is therefore not surprising that 
the two astrologers find different rulers for the year, as 
these are found from the figura cosli for the time of vernal 
equinox. These astrological predictions are like a cothurnus, 
which may be put on any foot, large or small ; and when he 
every year sends his Majesty a prognosticon, he only does 
it by the king's express command, although he does not 
like to have anything to do with such doubtful predictions, 
in which one cannot come to the truth, as in geometry and 
arithmetic, on which astronomy is founded, by means ot 
diligent observations. As to the two prognostications about 
which the Duke inquires, neither the Prutenic nor the 
Alphonsine tables are correct, as he had found by his own 
observations, and he had as usual sent the king a prog- 
nostic for the coming year, but had not kept a copy of it, 
and if the Duke wanted to see it, he might apply to the 
king about it. 

This letter shows with all desirable distinctness what 
Tycho thought of judicial astrology, with which philosophical 
speculations on the unity of the kosmos and the analogy 


between its celestial and terrestrial parts must by no means 
be confounded. He was not, like Kepler, obliged to waste 
liis time on work of that kind in order to get daily bread 
for timself and his family ; but he was highly paid, and 
his scientific researches were most liberally supported by 
the king, who could not be expected to appreciate their 
real value ; and it was only natural that h? should annually 
send the king an ofiering of a kind that the latter could 
understand, and which by the king was considered an 
acceptable gift. Tycho showed clearly enough in the horo- 
scopes which he drew up for the royal children that he 
was inclined to agree with Horace when he said — 

" Tu ne quEesieris, scire nefas, quern mibi, quem tibi 
Finem di dederint, Leuconoe, nee Babylonios 
Tentaris numeros." 

None of the almanacs which Tycho prepared for the king 
have been preserved, but a letter from the king is extant, 
dated 24th September 1587, in which he reminded Tycho 
about sending him the usual almanac for the ensuing year 
by the bearer of the letter, or, if it was not ready, as soon as 

Tycho doubtless obeyed the king's command, and it 
turned out to be the last time he had to do so. King 
Frederick II. died on the 4th April i 588, in his fifty-fourth 
year, to the great regret of Tycho, who owed him so much, 
as well as of the country at large. His character was open and 
chivalrous, and he was sincerely religious, while he at the 
same time tried to keep himself free from the intolerance 
prevailing everywhere in those days. He was less free 
from another weakness of his time, and, with characteristic 
frankness, Vedel said in a funeral oration, that " if His 
Grace could have kept from that injurious drink which is 
much too prevalent all over the world among princes and 

1 DansTce Magazin, ii. p. 247 (Weistritz, ii. p. 171). 


nobles and common people, then it would seem to human 
eyes and understanding that he might have lived for many 
years to come." But if he vs^as not better than his con- 
temporaries in this respect, he was at any rate far superior 
to most of them by honouring and protecting the peaceful 
student of science, and in the history of astronomy his name 
will always be gratefully remembered as long as that of 
Tycho Brahe continues to be reckoned among the heroes 
of science. 



The year 1588 is one of great importance in the life of 
Tycho Bralie, not only because his firm friend and bene- 
factor died in that year, but also because he then published 
a volume containing some of the results of his work at 
Uraniborg, and embodying his views on the construction 
of the universe. The subject specially dealt with in this 
volume was the great comet of 1577; the most conspicuous 
of the seven comets observed in his time. 

This comet was first noticed by Tycho on the 1 3th 
November 15 77) but it had already been seen in Peru 
on the 1st, and in London on the 2nd November.^ On 
the evening of the 13th, a little before sunset, Tycho was 
engaged at one of his fishponds, trying to catch some fish 
for supper, when he remarked a very brilliant star in the 
west, which he would have taken for Venus if he had not 

^ According to Tycho, it had been seen by mariners on the gth. In a copy 
of Cometm anno humanitatis 1577 a 10 winihris . . . adparcntis descriptio, 
by Bart. Scultetua (Gorlicii, 1578), which I picked up at Copenhagen some 
years ago, and which now belongs to the Royal Observatory, Edinburgh, 
there is written in a neat hand the following on the last blank page ; — 
" Ego Londini in Anglia oometam hoc libro descriptum, et 2 die Nouembris 
visum, tertio obseruare coepi ut potui radio nautico necdum sesquipedali, ita 
ut triangulum faceret cometa cum stellis subnotatis, caudse arcu comprehen- 
dente gradus 6ra.30 et amplius." [Then follow distance measures on Novem- 
ber 3, 9, 13, 15, 24, and 25, but without indication of time,] "Tanto lumine 
corruscabat hie cometes primo meo aspectu idque per nubes obuersantes, ut 
antequam integram ejus forniam vidissem, Lunam esse suspicarer, quam tamen 
eo turn loci et temporis lucere non potuisse statim, idque in tanto maiore 
adtniratione, coUigebam." 


THE COMET OF 1577. 159 

known that this planet was at that time west of the sun. 
Soon after sunset a splendid tail, 22° in length, revealed 
itself, and showed that a new comet had appeared. It was 
situated just above the head of Sagittarius, with the slightly 
curved tail pointing towards the horns of Capricornus, and 
it moved towards Pegasus, in which constellation it was 
last seen on the 26th January 1578. During the time it 
was visible Tycho observed it diligently, measuring with a 
radius and a sextant the distance of the head from various 
fixed stars, and occasionally also with a quadrant furnished 
with an azimuth circle (four feet in diameter), the altitude 
and azimuth of the comet. The sextant, which afterwards 
was placed in the large northern observing room at Urani- 
borg,-'- was constructed on the same principle as the one 
which Tycho had made at Augsburg in 1569, and was 
mounted on a convenient stand, which enabled the observer 
to place it in any plane he liked ; the arms were about four 
feet long. The quadrant was about 32 inches in semi- 
diameter, and the arc was graduated both by the transver- 
sals nearly always employed by Tycho, and by the concentric 
circles on the plan proposed by Nunez ; and on the back of 
the quadrant was a table, by means of which the readings 
of the latter could be converted into minutes without cal- 
culation.^ When observing this comet, Tycho had not yet 
at his disposal as many instruments and observers as in after 
years, nor had he as yet perceived the necessity of accurate 
daily time determinations by observing altitudes of stars, 
but merely corrected his clocks by sunset.^ The observa- 

^ Figured in De Mundi Mth. Rec. Phenom., p. 460, and Astr. Inst. Mech. 
ol. D. 6 verso. 

^ The quadrant is 6gured in De Mundi Jlth. Rec. PJien., p. 463, and Mech. 
fol. A. 2. 

^ The orbit of the comet of 1577 was computed from Tycho's sextant 
observations by P. Woldstedt, " De Gradu Praecisionis Positionura Comette 
Anni 1577 a celeberrimo T. B. . . . determinatarum et de fide elementorum 
orbitse," &c. Helsingsfors, 1844, '5 PP- 4to. 


tlons of tLis comet cannot tlierefore compare in accuracy with 
his later ones, but still they were immeasurably superior to 
those made by other observers, and they demonstrated most 
decisively that the comet had no perceptible parallax, and 
was consequently very far above the " elementary sphere " to 
which the Aristotelean philosophy had consigned all comets 
as mere atmospherical phenomena. By showing that the 
star of 1572 was situated among, _the stars, Tycho had 
already dealt the Aristoteleans a heavy blow, as it was now 
) clear that new bodies could appear in the aethereal regions. 
But still that star was not a comet, and Tycho, who had 
formerly believed in the atmospherical origin of comets, 
now took the opportunity of testing this matter, and found 
that the comet had no appreciable daily parallax. Though 
he was not the only observer who placed the comet beyond 
the moon, his observations were known by his contempo- 
raries to be of very superior accuracy, and his authority 
was so great that this question was decided once for 

Before proceeding to pass in review the book which 
Tycho prepared on this comet, we shall shortly allude to 
the other comets observed at Hveen. On the loth October 
1580 Tycho found a comet in the constellation Pisces. It 
was observed at Hveen till the 25 th November, and again 
after the perihelium passage on the morning of the 1 3th 
December. The observations are more numerous and better 
than those of the previous comet, and time determinations 
with a quadrant were made nearly every night, while 
there are very few quadrant observations of the comet. 
Moestlin had seen it already on the 2nd October, and both 
he and Hagecius observed it assiduously, but their observa- 


^ Except that Scipione Chiaramonte and an obscure Scotchman, Crai", 
vainly endeavoured to deduce the very opposite result from Tycho's observa- 
tions, but they were easily reduced in absurdum. 

THE COMET OF 1^77. 161 

tions are worthless compared witli Tycho's.'' The next 
comet was visible in May 1582, and was observed by Tycho 
on three nights Only, the 12th, 17th, and i8th, after which 
date the strong twilight prevented further observations; 
but in Germany it was still seen on the 23rd, and in China 
it was seen for twenty days after the 20th May.^ Of 
greater interest are the observations of the comet of i 5 8 S j 
which appeared at a time when Tycho's collection of instru- 
ments was complete, and when he was surrounded by a 
staff of assistants. The comet was first seen by Tycho on 
the 1 8th October after a week of cloudy weather, but at 
Cassel it had already been seen on the 8th {st. v.)? Tycho 
compares its appearance when it was first seen with the 
cluster (or nebula, as it was then called) Prsesepe Cancri, 
without any tail. The observations are very numerous, and 
were made partly with a sextant, partly with the large 
armillee at Stjerneborg, with which newly- acquired instru- 
ment the declinations of the comet and the difference of 
right ascension with various bright stars were observed at 
short intervals on every clear night up to the 1 2 th Novem- 
ber. The excellence of the observations and the care with 
which the instruments were treated are fully demonstrated 
by the most valuable memoir on this comet by C. A. F. 
Peters.* We have already mentioned that this comet gave 
rise to the correspondence between Tycho and the Land- 
grave and Rothmann. The next comet appeared in 1590, 

1 The orbit was determined by Schjellerup from a complete discussion o£ 
Tycho's sextant observations (Det kgl. danske Yidenshabemes Sdskabs Skrifier, 
math. Afdeling, 5te Raekke, 4de Bind, 1854). 

^ The orbit is very uncertain. D'Arrest, Astr. Nachr., xxxviii. p. 35. 

' Tycho returned home from Copenhagen on October iSth. Elias Olsen 
Morsing had seen it on the loth, as he wrote in the meteorological diary, 
" Stdlam vjTWtam vidi." See also Introduction to the Observations. 

■• Astr. iVacAr., vol. xxix. The observations had been published by Schu- 
macher in 1845 (Observationes cometce anni 1585 Uraniburgi habitce a Tyohone 
Brahe. Altona, 4t»). 

(' 11 


and was observed from the 23rd February to tte 6tli March 
inclusive, the declination with the armillas, altitudes and 
azimuths with a quadrant, and distances with a sextant. 
The time determinations are numerous.^ In July and 
August 1593 a comet appeared near the northern horizon. 
It was not observed at Hveen, but only by a former pupil of 
Tycho's, Christen Hansen, from Elbe in Jutland, who at 
that time was staying at Zerbst in Anhalt. He had only 
a radius with him, and his observations were therefore not 
better than those made by the generality of observers in 
those days.^ The last comet observed at Hveen was that 
of 1596, which was first seen by Tycho at Copenhagen 
on the 1 4th July, south of the Great Bear. It was not 
properly observed till after his return home on the 17th, 
and then only on three nights. It was last seen on the 
27th July.' 

The star of I $72 and the comets observed at Hveen had 
cleared the way for the restoration of astronomy by helping 
to destroy old prejudices, and Tycho therefore resolved to 
write a great work on these recent phenomena which should 
embody all results of his observations in any way bearing 
on them. The first volume he devoted to the new star, but 
as the corrected star places which were necessary for the 
reduction of the observations of i 5 7 2—7 3 involved researches 
on the motion of the sun, on refraction, precession, &c., the 
volume gradually assumed greater proportions than was origi- 
nally contemplated, and was never quite finished in Tycho's 

^ Orbit computed by Hind, Astr. Nadir., xxv. p. iii. 

^ Orbit by Lacaille, in Pingr^'s Comitographie, i. p. 560. 

3 Orbits by Hind and Valz, Astr. Nachr., xxiii. pp. 229 and 383 ; the ob- 
servations are published ibid., p. 371 et seq. Pingrd gives the results of most 
of the observations of the seven comets from a copy of them which is still 
preserved at the Paris Observatory. A complete edition of all the observa- 
tions was published in 1867 at Copenhagen, under the supervision of D'Arrest, 
Tychonia Brake Dani Ohservationes Sepfem Cometarum. Nune primum edidit 
F. B. Friis. 4to. 

THE COMET OF 1577. 163 

lifetime. On account of tlie wider scope ot its contents he 
gave it the title Astronomiw Instauratce Progymnasmata, or 
Introduction to the New Astronomy, a title which marks the 
work as paving the way for the new planetary theory and 
tables which Tycho had hoped to prepare, but which it fell 
to Kepler's lot to work out in a very different manner from 
that contemplated by Tycho. The second volume was 
devoted to the comet of 1577, and as the subject did not 
lead to the introduction of extraneous matter, this volume 
was finished long before the first one. The third volume 
was in a similar manner to treat of the comets of i 580 and 
following years, but it was never published, nor even written, 
though a great deal of material about the comet of 1585 
was put together and first published in 1 845 with the 
observations of this comet.-' 

The two volumes about the new star and the comet of 
1577 were printed in Tycho's own printing-office at Urani- 
borg, and after some delay caused by want of paper, the 
second volume was completed in 1588.^ The title is 
" Tychonis Brahe Dani, De Mundi aetherei recentioribus 
phsenomenis Liber secundus, qui est de illustri stella cau- 
data ab elapso fere triente Nouembris anno mdlxxvii usque 
in finem Januarii sequentis couspecta. Vraniburgi cum 
Privilegio." The book is in demy 4to, 465 pp., and the 

' The third volume is alluded to in several places in Tycho's writings, e.g. 
Progym., i. pp. 513 and 714 ; £pist., pp. 12, 20, 104, &o. 

^ In the above-mentioned letter to Below, Tycho wrote in December 1587 
that he should soon be in want of paper for a book which was being printed 
in his office, and had applied to the managers of two paper-mills in Mecklen- 
burg without getting an answer. He therefore asked Below to write to 
the managers of these mills, and to ask some friend at the Duke's court to 
intercede for him ; that he would willingly pay for the paper, which might be 
sent through his friend Bruoaeus at Rostock. Below wrote at once (28th 
December 1587) to Duke Ulrich, and asked him to do Tycho this favour, " der 
loblichen Kunst der Astronomic zur Beforderung " (Lisch, I. c, p. 6). To 
avoid a repetition of ^this inconvenience the paper-mill at Hveen was built a 
' few years later. 


colopiton is the vignette " Svspiciendo Despicio," with the 
words underneath " Uranibvrgi In Insula Hellesponti Danici 
Hvenna imprimebat Authoris Typographus Christophorus 
Weida. Anno Domini mdlxxxviii." 

The book is divided into ten chapters. The first contains 
most of the observations of the comet ; the second deduces 
new positions for the twelve fixed stars from which the dis- 
tance of the comet had been measured. Tycho mentions 
that while the comet was visible he had not yet any armillge, 
and he therefore carefully placed a quadrant in the meridian, 
and thus determined the declination of the star, and by the 
time of transit (through the medium of the moon and the 
tabular place of the sun) also the right ascension. He does 
not give any particulars about the observations and method, 
but he goes through the computations of the latitude and 
longitude of each star from the right ascension, declination 
and the point of the ecliptic culminating with the star. In 
a note at the end of the chapter he gives improved star 
places from the later observations with better instruments 
and methods, and, as might be expected, these later results 
are really much better than those found in I578.-'' .In the 
third chapter the longitude and latitude of the comet for 
each day of observation are deduced from the observed dis- 
tances from stars ; but though he gives diagrams of all the 
triangles, and gives all the numerical data, the trigonome- 
trical process is not shown. In the fourth chapter the. right 
ascensions and declinations of the comet are computed from 
the longitudes • and latitudes.^ The fifth deals with the deter- 

^ In the above-mentioned paper Woldstedt compares the two sets of posi- 
tions with modern star places (Abo or Pond with proper motions from Bessel's 
Bradley or Abo). The means of the errors of Tycho's places, irrespective of 
sign, are in longitude and latitude, for the older positions, 4'.8 and l'. I, for 
the later ones, l'.4 and i'.5. About the methods by which these positions were 
found, see (Chapter XII.' 

^ By the method of Al Battani, which employs the point of the equator having 
the same longitude as the comet. Delambre, Astr. du Moyen Age, p. 21. 

THE COilET OF 1577. 165 

mination of the inclination and node of the apparent path 
of the comet with regard to the ecliptic, which Tvcho found 
from two latitudes and the arc of t;ie ecliptic between them ; 
seven diS'erent combinations give results which only difer a 
few minutes inter se. The sixth chapter is a more lengthy one, 
and treats of the distance of the comet from tlie earth ; aad 
as this was of paramount importance as a test of the Aiisto- 
te'ean doctrine, he endeavours to determine the parallax in 
several different ways. First, he shows that the comet had 
ELOved in a great circle, and though not with a uniform velo- 
city throusliont; yet with a very gradually decreasing one ; 
and if it had been a mere " meteor " in our atmosphere, it 
would have moved by fits and starts, and not in a great circle. 
The velocity never reached half that of the moon, the nearest 
celestial body. He next discusses two distance measures 
from e Pegasi, made on the 23 rd Xovember, with an inter- 
val of three hours, and finds that if the comet had been at 
the same distance from the earth as the moon,^ the parallax 
would have had the effect of making the second angular 
distance from the star equal to the first, even after allowing 
for the motion of the comet in the interval, while the second 
observed distance was 12' smaller than the first one. At 
least the comet must have been at a distance six times as 
great as that of the moon, and all that can be concluded 
from the distance measures is that the comet was far beyond 
the moon, and at snch a distance that its paraUax could not 
be determined accurately. The same appears from compari- 
sons between distance measures from stars made at Hveen 
and those made at Prague by Hagecius, which should differ 
six or seven minutes if the comet was as near as the rcoon, 
whereas they only differed one or two minutes. The obser- 
vations of Cornelius Gemma at Lonvain, when compared with 
those at Hveen, point in the same direction, but are much 

' Which he, with Copemicns, assumes = 52 semi-diameters of the earth. 


too inaccurate to build on. Again, Tyclio takes two obser- 
vations of altitude and azimuth ; from the first he computes 
the declination, corrects this for the motion of the comet in 
the interval, and with this and the second azimuth computes 
the altitude for the time of the second observation. For a 
body as near as the moon there would be a considerable 
difierence, while several examples show none. Finally, Tycho 
employs the method of Eegiomontanus for finding the actual 
amount of parallax from two altitudes and azimuths, but 
several combinations gave the same result, that no parallax 
whatever could be detected in this way. Tycho was well 
aware that this was a bad method, and evidently only tried 
it as a duty.-*- (The comet of 1585 was chiefly observed 
with the large armillse, and the want of parallax was 
demonstrated by comparing the right ascension and declina- 
tion observed with an interval of some hours with the daily 
motion of the comet.^) 

In the seventh chapter the position of the comet's tail 
is examined. The increased attention which had been paid 
to comets during the sixteenth century had led to the dis- 
covery of the fact that their tails are turned away from the 
sun, and not only Peter Apianus, who is generally credited 
with the discovery, but also Fracastoro, and after them 
Gemma and Cardan, had pointed out this remarkable fact 
from observations of diflferent comets. Tycho, who took 
nothing on trust, examined the matter, and computed from 
twelve observations of the direction of the tail of the comet 
of 1577 the position of the tail with regard to a great 
circle passing through the sun. He found that the direc- 

1 See his remarks about the method, De mtindi ceth. rec. phen., p. 156, and 
in a letter to Hagecius (who had found a parallax of five degrees by the 
method), T. B. et doct. vir. Eplst., p. 60. Delambre sets forth the method 
with his usual prolixity in Bist. de I'Astr. du Moyen Age, p. 341 ; Astr. Moderne, 
i. p. 212 et seq. 

- Spist. Astron., pp. 16-17. 

THE. COMET OF 1577. 167 

tion of the tail never passed exactly through the sun, but 
seemed to pass much nearer to the planet Venus ; he adds, 
that though the statement of Apianus was only approxi- 
mately true, the opinion of Aristotle was far more erroneous, 
for according to him, the tails, as lighter than the head, 
should be turned straight away from the centre of the 
earth. The curvature he considers merely an illusion, 
caused by the head and the end of the tail being at dif- 
ferent distances from the earth. 

The eighth chapter is the most important in the whole 
book, as the consideration of the comet's orbit in space 
leads Tycho to explain his ideas about the construction of 
the universe. The " sethereal world," he says, is of wonder- 
fully large extent ; the greatest distance of the farthest 
planet, Saturn, is two hundred and thirty-five times as 
great as the semi-diameter of the " elementary world " as 
bordered by the orbit of the moon. The moon's distance 
he assumes equal to fifty-two times the semi-diameter of 
the earth, which latter he takes to be 860 German miles.'' 
The distance of the sun he believes to be about twenty 
times that of the moon. In this vast space the comet has 
moved, and it therefore becomes necessary to explain shortly 
the system of the world, which he had worked out " four 
years ago," i.e., in 1583.^ The Ftolemean system was too 
complicated, and the new one which that great man Coper- 
nicus had proposed, following in the footsteps of Aristarchus 
of Samos, though there was nothing in it contrary to 
mathematical principles, was in opposition to those of 
physics, as the heavy and sluggish earth is unfit to move 

' The value for the earth's semi-diameter was probably talcen from Fernels 
well-known Cosmotheoria, Paris, 1528. We shall see in the next chapter what 
ideas Tyoho had formed as to the distance of the outer planets and the fixed 
stars [Progym., i. p. 465 et seq.). 

2 The book was written in 1587, as appears from several allusions to 
time in it. 



and tlie system is even opposed to the autliority of Scrip- 
ture. The vast space which would have to be assumed 
between the orbit of Saturn and the fixed stars (to account 
for the want of annual parallax of these), was another 
diflSculty in the Copernican system, and Tycho had there- 
fore tried to find a hypothesis which was in accordance with 
mathematical and physical principles, and at the same time 
would not incur the censure of theologians. At last he 
had, " as if by inspiration," been led to the following idea 
on the planetary motions. 

The Tyohobio Sistem op the Wokld. 

The earth is the centre of the universe, and the centre of 
the orbits of the sun and moon, as well as of the sphere 
of the fixed stars, which latter revolves round it in twenty- 


four hours, carrying all the planets with it. The sun is the 
centre of the orbits of the five planets, of which Mercury 
and Venus move in orbits whose radii are smaller than that 
of the solar orbit, while the orbits of Mars, Jupiter, and 
Saturn encircle the earth. This system accounts' for the 
irregularities in the planetary motions which the ancients 
explained by epicycles and Copernicus by the annual motion 
of the earth, and it shows why the solar motion is mixed up 
in all the planetary theories.'^ The remaining inequalities, 
which formerly were explained by the excentric circle and 
the deferent, and by Copernicus by epicycles moving on 
excentric circles, could also, in the new hypothesis, be ex- 
plained in a similar way. As the planets are not attached 
to any solid spheres, there is no absurdity in letting the 
orbits of Mars and the sun intersect each other, as the 
orbits are nothing real, but only geometrical representations. 

This is all which Tycho considered it necessary to set 
forth about his system in the book on the comet, but he 
stated his intention of giving a fuller account of it on a 
future occasion, which never came. We shall finish our 
account of his labours connected with the comet of i 5 7 7 
before we consider his system a little more closely. 

The comet was by Tycho supposed to move round the 
sun in an orbit outside that of Venus, and in the direction 
opposite to that of the planets, the greatest elongation from 
the sun being 6o°. He was unable to represent the observed 
places of the comet by a uniform motion in this orbit, and 
was obliged to assume an irregular motion, slowest when in 
inferior conjunction, increasing when the comet was first 
discovered, and afterwards again decreasing., Tycho remarks 

1 This alludes to the circumstance, which had appeared so strange to the 
ancients, that the period of the motion of each upper planet in its epicycle 
was precisely equal to the synodical period of the planet, while in the case of 
the two inferior planets the period in the deferent in the Ptolemean system 
was equal to the sun's period of revolution. 


that an epicycle miglit be introduced to account for this, but 
as tlie inequality was only 5', lie did not deem it necessary 
to go so far in refining the theory of a transient body like 
a comet ; and besides, it is probable that comets, which only 
last a short time, do not move with the same regularity as 
the planets do. He finds the inclination of the orbit to the 
ecliptic equal to 29° 15', and shows how to compute the 
place of the comet for any given time by means of the table 
of its orbital motion with which he concludes the first part 
of the book. The ninth chapter is a very short one, and 
treats of the actual size of the comet ; as the apparent 
diameter of the head on the 1 3th November was 7', the 
diameter was 368 miles, or ti of the diameter of the earth. 
Similarly he calculates the length of the tail, and finds it 
equal to 96 semi-diameters of the earth. This is on the 
assumption that the taU is really turned away from Venus, 
and though he adds that he had also found this to be the 
case with the comet of 1582, he suspects that some optical 
illusion must be the cause of this, as it would be more 
natural that the tail should be turned from the sun than 
from Venus. In a letter to Rothmann in 1589, he ex- 
presses the opinion that the tail is not a mere prolongation 
of the head, for in 1577 head and tail were of a different 
colour, and stars could be seen through the tail. He 
apparently thought that the tail was merely an effect of 
the light from the sun or Venus shining through the head, 
and referred to the opinion of Benedict of Venice that 
the illumination of the dark side of the moon was due to 
Venus, about which he, however, does not express any 
decided opinion."^ 

The only part of the tables of the comet's motion which 
requires notice is that relating to the horizontal parallax. 
This he makes out from his theory to have been nearly 20' 

1 Epist, astron., p. 142. 


in the beginning of November, and then rapidly to have 
decreased ; and, as an excuse for this considerable quantity 
not having been detected, he adds his belief that refraction 
would counteract the parallax near the horizon where the 
comet was observed. 

The remainder of Tycho's book is devoted to a detailed 
examination of the writings and observations of other 
astronomers on the comet. This was the first comet which 
gave rise to a perfect deluge of pamphlets, in which the 
supposed significance of the terrible hairy star was set 
forth, and for more than a century afterwards every comet 
was followed by a flood of effusions from numberless scrib- 
blers. The astrological significance of the comet Tycho does 
not trouble himself about, though he takes the opportunity 
of stating that he does not consider astrology a delusive 
science, when it is kept within bounds and not abused by 
ignorant people. For the sun, moon, and fixed stars would 
have suflSced for dividing time and adorning the heavens, 
and the planets must have been created for some purpose, 
which is that of forecasting the future.^ But he goes 
through the observations or speculations of eighteen of his 
contemporaries, taking first those who had acknowledged 
the comet to be beyond the lunar orbit (Wilhelm IV., 
Moestlin, Cornelius Gemma, and Helisseus Eoeslin), and 
afterwards the great herd of those who believed it to move 
in the "elementary world." Among these there are no 
generally known names except those of Hagecius and 
Scultetus. A theory very like that of Tycho was proposed 
by Moestlin, who also 'let the comet move in a circle round 
the sun outside the orbit of Venus, and accounted for the 
irregular motion by a small circle of libration perpendicular 
to the plane of the orbit, along the diameter of which the 
comet moved to and fro. This idea was borrowed from 

1 Be mundi osth. rec. phen., p. 287. Compare above, Chapter IV. p. 75. 


Copernicus, whose lead Moestlin also followed with regard 
to the motion of the earth . 

That the great Danish astronomer did not become con- 
vinced of the truth of the Copernican system, but, on the 
contrary, set up a system of his own founded on the im- 
movability of the earth, may appear strange to many who 
are unacquainted with the state of astronomy in the six- 
teenth century, and it may to them appear to show that he 
cannot have been such a great reformer of astronomical 
science, as is generally supposed. But it is not necessary 
to concoct an apology for Tycho ; we shall only endeavour 
to give an intelligible and correct picture of the state of 
science at that time with regard to the construction of the 

That Copernicus had precursors among the ancients who 
'taught that the earth was in motion, is well known, and 
he was well aware of this fact himself But none of 
J_ those precursors had done more than throw out their ideas 
for the consideration of philosophers ; they had not drawn 
the scientific conclusions from those ideas, and had not 
worked them into a complete system by which the compli- 
cated motions of the planets could be accounted for and 
made subject to calculation. Neither had this been done 
by the philosophers who made the earth the centre of the 
universe, and let it be surrounded by numerous solid crystal 
spheres to which the heavenly bodies were attached. All 
this was only philosophical speculation, and was not founded 
on accurate observations ; but the only two great astronomers 
of antiquity, Hipparchus and Ptolemy, have handed down 
to posterity a complete astronomical system, by which the 
intricate celestial motions could be explained and the 
positions of the planets calculated. But this " Ptolemean 
system," in which a planet moved on an epicycle, whose 
centre moved on another circle (the deferent), with a velo- 


city which was uniform with regard to the centre of a 
third circle, the equant/ was only a most ingenious mathe- 
matical representation of the phenomena— a working hypo- 
thesis ; it did not pretend to give a physically true descrip- 
tion of the actual state of things in the universe.^ No 
doubt there were many smaller minds to which this did 
not become clear, but both by the great mathematician who 
completed it, and by astronomers of succeeding ages the 
Ptolemean system was merely considered a mathematical 
means of computing the positions of the planets. 

When astronomy towards the end of the fifteenth century 
again began to be cultivated in Europe, the inconvenience 
of the extremely complicated system became felt, and soon 
the great astronomer of Prauenburg conceived how a dif- 
ferent system might be devised on the basis of the earth's 
motion round the sun. But Copernicus did a great deal 
more than merely suggest that the earth went round the 
sun. He worked out the idea into a perfect system, and 
developed the geometrical theory for each planet so as to 
make it possible to construct new tables for their motion. 
And though he had but few and poor instruments, and did 
not observe systematically, he took from 1497 to 1529 
occasional observations in order to get materials for finding 
the variations of the elements of the orbits since the time 

^ The earth, the centre of the deferent, and the centre of the equant were 
in a straight line and equidistant ; only in the case of Mercury the centre of 
the equant was midway between the earth and the centre of the deferent. 

^ Perhaps we may illustrate this by an example from modern science. 
When the deflection of a magnetic needle in the neighbourhood of an electric 
current was first discovered, some difficulty was felt in giving a rule for the 
direction in which either pole of a needle is deflected by a current, whatever 
their relative positions may be, until Ampere suggested that if we imao-ine a 
human figure lying in the current facing the needle, so that the current 
comes in at his feet and out at his head, then the deflection of the north- 
seeking pole will be to his left. Nobody ever suspected Ampere of believing 
that there really was a little man lying in the current, but to many people in 
the Middle Ages the epicycles were doubtless really existing. 


of Ptolemy. He was therefore able to produce a complete 
new system of astronomy, the first since the days of the 
Alexandrian school, and the first of all which gave the 
means of determining the relative distances of the planets. 
And it was in this way that he showed himself as the great 
master, and was valued as such by Tycho Brahe, who was 
better able than any one else to appreciate Copernicus, since 
his own activity left no part of astronomy untouched. But 
unfortunately the edifice which Copernicus had constructed 
was not very far from being as artificial and unnatural 
as that of Ptolemy. The expedient of letting the earth 
move in a circular orbit round the sun could ' explain 
those irregularities in the planetary motions (stations and 
retrogradations) of which the synodic revolution was the 
period (the second inequalities, as the ancients had called 
them), because they were caused by the observer being 
carried round by the moving earth. But this could not 
account for the variable distance and velocity (the first 
inequality) of which the orbital revolution was the period, 
and of which Kepler gave the explanation when he found 
that the planets move in ellipses, and detected the law which 
regulates the velocities in these. Until Kepler had dis- 
covered the laws which bear his name, there was no way of 
accounting for these variations, except by having recourse 
to the same epicycles and excentrics which Ptolemy had 
used so liberally ; and the planetary theory of Copernicus 
was therefore nothing but an adaptation of the Ptoleinean 
syst em to the heliocentric idea.^ And the motions were"~not 
referred to the real place of the sun, but to the middle sun, 
i.e., to the centre of the earth's orbit, while the orbit of 
Mercury required a combination of seven circles, Venus of 

1 The chief claim of the system of Copernicus to be considered simpler 
than the Ptolemean was that it dispensed with the eqnant (which really 
violated the principle of uniform motion, so much thought of), and let the 
motion on the deferent be uniform with regard to its centre. 


five, tbe earth of three, the moon of four, and each of the 
three outer planets of five circles; and even with this 
complicated machinery the new system did not represent 
the actual motions in the heavens any better than the 
Ptolemean did. Copernicus himself said that he would be 
as delighted as Pythagoras was when he had discovered his 
theorem, if he could make his planetary theory agree with 
the observed positions of the planets within i o'.'' But the 
accuracy was very far indeed from reaching even that limit. 
Doubtless the Prutenic tables were better than the Alphon-> 
sine ones, but that was simply because Copernicus had been 
able to apply empiric corrections to the elements of the 
orbits, and because Eeinhold did his work better than the 
numerous computers at Toledo had done theirs. The 
Copernican system as set forth by Copernicus, therefore, did 
not advance astronomy in the least ; it merely showed that 
it was possible to calculate the motions of the planets with- 
out having the origin of co-ordinates in the centre of the 
earth. But of proofs of the physical truth of his system 
Copernicus had given none, and could give none ; and though 
there can hardly be any doubt that he himself believed in 
the reality of the earth's motion, it is extremely difficult to 
say of most of his so-called followers whether they had any 
faith in that motion, or merely preferred it for geometrical 

It is always difficult to avoid judging the ideas of former 
ages by our own, instead of viewing them in their connection 
with those which went before them and from which they 

^ Ehetici Ephemerides novw, 1550, p. 6. 

' Mbbius has shown that the use of the mean place of the sun {i.e., the 
centre of the earth's orbit) instead of the true place might, in the Copernican 
theory of Mars, lead to errors of 2°. See a note in Apelt's Die Seformation 
der SUrnlmnde, Jena, 1852, p. 261. 

' The contemporaries of Copernicus were not aware that the introduction 
to his book, in which the system is spoken of as a mere hypothesis was 
written without the knowledge of the author by Osiander of Niiruberg. 


were developed. Tlie physical objections to the earth's 
motion, which to us seem so easy to refute, were in the 
sixteenth century most serious difficulties, and the merits of 
Galileo in conceiving the principles of elementary mechanics 
and fixing them by experiments must not be underrated. 
Neither should the advantage be forgotten which the seven- 
teenth century had over the sixteenth from the invention of 
the telescope, which revealed the shape of the planets, the 
satellites of Jupiter, and the phases of Venus, and thus 
placed the planets on an equal footing with the earth, to 
which the unassisted vision could never have seen any 
similarity in them. 

Tycho Brahe evidently was not content with a mere 
geometrical representation of the planetary system, but 
wanted to know how the universe was actually constructed. 
He felt the " physical absurdity " of letting the earth move, 
but, on the other hand, the clearness of mind which made 
him so determined an opponent of the scholastic philosophy 
enabled him to see how unfounded some of the objections to 
the earth's motion were. In a letter to Rothmann in 1587 
Tycho remarks that the apparent absurdity is not so great 
as that of the Ptolemean idea of letting a point move on 
one circle with a velocity which is uniform with regard to 
the centre of- another circle. He adds that the objections 
which Buchanan had made to the revolution of the earth in 
his poem on the sphere are futile, since the sea and the air 
would revolve with the earth without any violent commotion 
being caused in them.'' But all the same he thought that 
a stone falling from a high tower ought to fall very far from 
the foot of the tower if the earth really turned on its axis. 
This remark is made in another letter to Eothmann in 
1589, in which he made several objections to the annual 
motion of the earth.^ The immense space between Saturn 

1 Epist. astron., p. 74. 2 Ibid., p. 167. 


and tlie fixed stars would be wasted. And if the annual 
parallax of a star of the third magnitude was as great 
as one minute, such a star, which he believes to have an 
angular diameter of one minute, would be as large as the 
annual orbit of the earth. And how big would the brightest 
stars have to be, which he believes to have diameters of 
two or three minutes ? And how enormously large would 
they be if the annual parallax was still smaller ? ^ It was 
also very difficult to conceive the so-called " third motion " 
of the earth, which Copernicus (so needlessly) had introduced 
to account for the immovable direction of the earth's axis. 

Tycho alludes in several places to the difficulty of recon- 
ciling the motion of the earth with certain passages of 
Scripture.^ He was far from being the only one who 
believed this difficulty to be a very serious one against 
accepting the new doctrine. The Eoman Church had not 
yet taken any official notice of the Copernican system, but 
in Protestant countries the tendency of the age was de- 
cidedly against the adoption of so stupendous a change in 
cosmological ideas. Nobody cared to study anything but ': 
theology, and theology meant a petrified dogmatism which 
would not allow the smallest iota in the Bible to be taken 
in anything but a strictly literal sense. Luther had in his 
usual pithy manner declared what he thought of Copernicus,' 
and even Melanchthon, who was better able to take a dis- 
passionate view of the matter, had declared that the authority 

^ Tycho had in vain tried to find an annual parallax of the pole star and 
other stars. Letter to Kepler, December 1599, Kepleri Opera Omnia, viii. 
p. 717. 

^ Epist, p. 148. He says here that Moses must have known astronomy, 
since he calls the moon the lesser light, though sun and moon are apparently 
of equal size. Therefore the prophets must also be assumed to have known 
more about astronomy than other people of their time did. 

' " Der Narr will die ganze Kunst Astronomiil umkehren ! Aber wie die 
heilige Schrift anzeigt, so hiess Josna die Sonne still stphen und nicht das 
Erdreioh." — Luther's Tischreden, p. 2260. 



of Scripture was against accepting the theory of the eairth's 
motion.-"^ This may have had some weight with Tycho, at least 
it might at first have made him indisposed openly to advocate 
the Copernican system, as the most narrow-minded intoler- 
ance was rampant in Denmark (as in most other countries), 
notwithstanding the king's more liberal disposition. But 
the king did not wish to be considered unorthodox, and had 
yielded to the importunity of his brother-in-law, the Elector 
of Saxony, by dismissing the distinguished theologian Niels 
Hemmingsen from his professorship at the University, as 
suspected of leaning to Calvinism. It would certainly not 
! have been prudent for the highly-salaried and highly-envied 
pensioner of the king, to declare himself an open adherent 
of a system of the world which was supposed not to be 

How far this consideration influenced Tycho it is not 
easy to decide, but the supposed physical difficulties of the 
Copernican system and a disinclination to adopt a mere 
geometrical representation, in the reality of which he could 
not believe, led him to attempt the planning of a system 
which possessed the advantages of the Copernican system 
without its supposed defects. In a letter to Rothmann in 
1589^ Tycho states that he was induced to give up the 
Ptolemean system by finding from morning and evening 
observations of Mars at opposition (between November 1582 
and April 1583) that this planet was nearer to the earth 
than the sun was, while according to the Ptolemean system 
the orbit of the sun intervened between that of Mars and 
the earth. To the modern reader who knows that the 
horizontal parallax of Mars can a(t most reach about 23 , 

^ Melanohthon's Initia doctrinal pTiysicai, in the chapter " Quis est motus 

' Epist. astr., p. 148 ; see also ibid., p. 42, and letter to Peucer of 1588, 
Weistritz, i. p. 243. 


a quantity which Tycho's instrumeuts could not possibly 
measure, this looks a surprising statement, particularly 
when it is remembered that Tycho, like his predecessors, 
assumed the solar parallax equal to 3'. This mystery was 
believed to have been solved by Kepler, who states that he 
examined the observations of 1582—83, and found little or 
no parallax from them ; but, to his surprise, he found among 
Tycho's manuscripts one written by one of his disciples, iu 
which the observed places were compared with the orbit of 
Mars according to the planetary theory and numerical data 
of Copernicus, and a most laborious calculation of triangles 
ended in the result that the parallax of Mars was greater 
than that of the sun. Kepler suggests that Tycho meant 
his pupil to calculate the parallax from the observations, 
but that the pupil, by a misunderstanding, worked out the 
distance of Mars from the diameters of the excentrics and 
epicycles of Copernicus.^ The subject of the parallax of 
Mars is alluded to by Tycho in a letter to Brucseus, written 
in 1584. Here he does not hint at having already con- 
structed a new system himself, but merely tries to disprove 
that of Copernicus, and among his arguments is, that, ac- 
cording to Copernicus, Mars should in 1582 have been at a 
distance equal to two-thirds of that of the sun, and conse- 
quently have had a greater parallax, whereas he found by 
very frequent and most exquisite observations that Mars had 
a far smaller parallax, and therefore was much farther from 
us than the sun.^ In other words, Tycho could not find 
any parallax of Mars from his observations, but somehow 
he afterwards imagined that he had found Mars to be nearer 

^ Kepler, De motibus stdlce Mortis, ch. xi., Opera omnia, iii. p. 219 ; see also 
p. 474. In his Progymnasmata, i. p. 414, Tycho says that the outer planets 
have scarcely perceptible parallaxes, but that he had found by an exquisite 
instrument that Mars at opposition was nearer than the sun. On p. 661 he 
alludes to it again. 

^ T. Brahei et doct. vir. Epistolw, p. 76. 


the earth at opposition than the sun was, and this decided 
him to reject the Ptolemean system. He adds in his letter 
to Eothmann, that the comets when in opposition did not 
move in a retrograde direction like the planets, for which 
reason he had' to reject the Copernican system also. It did 
not strike him that comets might move in orbits greatly 
differing from those of the planets. Having rejected the 
two existing systems, there was nothing to do but to design 
a new one. 

The Tychonic system could explain the apparent motions 
of the planets (including their various latitudes), and it 
might have been completed in detail by being furnished 
with excentrics and epicycles like its rival. Copernicus 
had referred the planetary motions, not to the sun, but to 
the centre of the earth's orbit, from which the excentrici- 
ties were counted, and through which the lines of nodes 
passed, so that the earth still seemed to hold an exceptional 
position. The Copernican system, so long as it was not 
purged of the artificial appendage of epicycles by the laws 
of Kepler, was not very much simpler than the Tychonic, 
and, mathematically speaking, the only difference between 
them was, that the one placed the origin of co-ordinates in 
the sun (or rather in the centre of the earth's orbit), the 
other in the earth.'' Tycho's early death prevented the 
turther development of the theory of the planets by his 
system, which he intended to do in a work to be called 
Theatrum astronomicum. He only gives a sketch of the 
theory of Saturn in the first volume of his book, in which 
the planet moves in a small epicycle in retrograde direction, 

^ Might Tj'cho have got the idea of his Bystem by reading the remark of 
Copernicus (De revol., iii. 15) when talking about the earth's orbit : " Estque 
prorsTis eadem domoustratio, si terra quiesceret atque Sol in circumcurrente 
moveretur, ut apud Ptolemseum et alios " ? According to Prowe (Nic, Cop- 
pernicus, Bd. i. Part 2, p. So9)> ^^™ 's one of the sentences struck out in the 
original MS., but reinserted by the editor of the first edition. 


making two revolutions while the centre of the small epi- 
cycle moves once round the circumference of a larger one 
in the same direction in which the centre of the latter 
moves along the orbit of Saturn.-^ 

The Tychonic system did not retard the adoption of the 
Copernican one, but acted as a stepping-stone to the latter 
from the Ptolemean. By his destruction of the solid spheres 
of the ancients and by the thorough discomfiture of the scho- 
lastics caused by this and other results of his observations 
of comets, he helped the Copernican principle onward far 
more effectually than he could have done by merely acqui- 
escing in the imperfectly formed system, which the results 
of his own observations were to mould into the beauti- 
ful and simple system which is the foundation of modern 

The book on the comet of i 577 was ready from the press 
in 1588, and though not regularly published as yet, copies 
were sent to friends and correspondents whenever an oppor- 
tunity offered.^ Thus Tycho's pupil, Gellius Sascerides, who 
in the summer of 1588 started on a journey to Germany, 
Switzerland, and Italy, brought copies to Rothmann and 
Maestlin, to whom he was also the bearer of letters.' The 
Landgrave did not receive a copy, but studied Kothmann's 
copy with great interest, and thought that it must have 
been meant for himself, until Rothmann suggested that it 
was only part of an unfinished work, and that he would get 
one later on, which of course he did as soon as Tycho heard 
of this incident. In the following' year, while he was at 
the fair of Frankfurt, Gellius received another copy of the 
book, which he was to bring to Bologna to Magini, and this 

^ Progymn., i. p. 477, where he also alludes to the " Commentariolus " of 
Copernicus, see above, p, 83). 

'■' The book was not for sale till 1603. There are three copies in the Royal 
Library at Copenhagen with the original title-page of 1 588. 

^ About Maestlin see Kepleri Oi^era, i. p. 1 90. 


lie forwarded from Padua in 1590, together with a letter 
in which he gave an account of the unfinished first volume 
of Tycho's work.^ A copy was sent to Tycho's old friend 
Scultetus, who let Monavius of Breslau partake of his joy 
over it. To Thomas Savelle of Oxford, a younger brother 
of the celebrated founder of the two Savillian professorships, 
who was then travelling on the Continent, Tycho sent two 
copies of the book, together with a letter in which he, 
among other things, asked him to remind Daniel Rogers 
about the copyright which he had promised to procure 
Tycho for his books in England.^ To Caspar Peucer, who 
had already heard of the book from Eantzov, Tycho sent a 
copy, and added a very long letter in which he entered 
fully into his reasons for rejecting the Copernican system, 
and discussed some passages of Scripture which had been 
made use of to prove the solidity of the celestial spheres. 
In this letter he also gives an interesting sketch of the plan 
of the great work to which the three volumes on the new 
star and comets were to be introductory. It was to consist 
of seven books ; the first was to describe his instruments, 
the second the trigonometrical formulse required in astro- 
nomy, the third the new positions of fixed stars from his 
observations, the fourth was to deal with the theories of the 
sun and moon, the fifth and sixth with the theories of 
the planets, the seventh with the latitudes of the planets.' 
With the exception of the first chapter (which he made 
into a separate book), the contents of this projected work 

' Carteggio inedito di Tieone Brake, Q. Keplero, <tc., con G. A. llagini Ed. 
Ant. Favaro, Bologna, 1886, p. 193. 

- A Collection of letters illustrative of the progress of science in England. 
Edited by J. O. HalliwelL London, 1841, p. 32. Tycho also sent Savelle four 
copies of his portrait engraved at Amsterdam (by Geyn, 1586), and inquired 
whether there were any good poets in England who would write an epigram 
on this portrait or in praise of his works. He added that Rogers might also 
show his friendship by helping him in this matter. 

'■' Weistritz, i. pp. 239-264, reprinted from Resen's Inscriptions Ha/nienses. 


(or at least the outlines of them) were afterwards incorpo- 
rated in Tycho's first volume of Progymnasmata. 

When Eothmann had received the book he wrote to 
Tycho to thank him for it, and remarked that the new 
system of the world seemed to be the same as one which 
the Landgrave a few years previously had got his instru- 
ment-maker to represent by a planetarium.-'' Tycho, who 
had kept his system a deep secret until the book was 
ready, was at first unable to understand from whom the 
Landgrave could have got a description of it,^ but he soon 
after received from a correspondent in Germany a recently 
published book which solved the riddle. The title of the 
book was Nicolai Raymari Ursi Dithmarsi Fundamenium 
asfronomicum, printed at Strassburg in 1588. The author, 
Nicolai Eeymers Bar, was a native of Ditmarschen, in the 
west of Holstein, and a son of very poor parents. He is 
even said to have earned his bread as a swineherd, but 
possessing great natural abilities, he rapidly acquired con- 
siderable knowledge both in science and in classics. In 
1 5 80 he published a Latin Grammar, and in 1 5 8 3, at Leipzig, 
a Geodaesia Banzoviana, dedicated to his patron, Heinrich 
Rantzov, Governor of Holstein.^ Having for some time 
worked as a surveyor, he seems to have entered the service 
of a Danish nobleman, Erik Lange of Engelholm, in Jut- 
land, who was a devoted student of alchemy. Lange went 
on a visit to Tycho in September 1584, and brought Reymers 
with him, but this probably somewhat uncouth self-taught 
man seems to have been treated with but scant civility 

' Epist. astron., pp. 128, 129. 

' So Tycho says in his reply to Rothmann {Epist., p. 149), but before 
Rothmann'a letter was written Tycho had in his letter to Peucer (dated 13th 
September 1588) mentioned that a German mathematician had two years 
previously heard of the system " per quondam meum fugitivum ministrum " 
(Weistritz, i. p. 255), and this he also mentions in the letter to Rothmann. 

' Kastner, Geschichte der Matliematik, i. p. 669 ; Kepleri Opera ed. Frisoh, 
i. p. 2i8. 


at Uraniborg. After having spent a winter as tutor in 
Pomerania, Reymers went to Cassel in the spring of 1586, 
where he informed the Landgrave that he had the previous 
winter, while living on the outskirts of Pomerania, designed 
a system of the world. This was esactly like Tycho's, 
except that it admitted the rotation of the earth. The 
Landgrave was so pleased with the idea, that he got Biirgi 
to make a model of the new system ; but though he had 
been well received at Cassel, Reymers was not long in 
favour there, as he fell out with Rothmann, to whom he 
abused Tycho. Rothmann mentioned this in a letter to 
Tycho in September 1586,^ but did not mention Reymers' 
system, which first became known in i S 8 8 by the above- 
mentioned book.^ This contains some chapters on trigono- 
metry and some on astronomy, and in the last chapter the 
new system is explained and illustrated by a large diagram 
on about twice as large a scale as that in Tycho's book. 
The only important difference is, that the orbit of Mars does 
not intersect that of the sun, but lies quite outside it. 

Tycho was apparently very proud of his system, and (as 
in the case of Wittich) he immediately jumped to the con- 
clusion that Reymers Bar had robbed him of his glory .^ 

^ Epist. astron., p. 33, where Eothmann (who thought that Keymers had 
been employed in Tycho's printing-office) calls him a dirty blackguard (" plura 
soriberem, praesertim de impure illo nebulone "), which expression Tycho now 
found very suitable (ibid., p. 149). 

^ For accounts of this book see Kastner, i. p. 631 ; Delambre, Astron. 
moderne, i. p. 287 ; and Rudolf Wolf's Astronomische Miitheilvmgen, No. 

' Already in 1589 or 1590 Duncan Liddel lectured at Rostock on the 
Tychonio system, calling it by this name. A report afterwards reached Tycho 
to the effect that Liddel privately took the credit of the new system to him- 
self, and that he later on did so openly at Helmstadt (see letter from Cramer, 
a clergyman of Rostock, to Holger Rosenkrands, in Epistolae ad J. Kepplerum, 
ed. Hanschius, p. 114 ci seq.). It appears, however, that Liddel indignantly 
denied the charge, though he claimed to have deduced the system himself, 
and to owe Tycho nothing except the incitation to speculate on the matter, 
for which reason he had mentioned the system as the " Tychonio " [Kepleri 
Opera omnia, i. pp. 227, 228). 


He wrote at once to Kothmann (in February 1589) that 
Eeymers must have seen a drawing of the new system 
during his stay at Uraniborg in I 5 84, and as a proof of 
this he refers to the orbit of Mars, which in a drawing 
made before that time, by a mistake, had been made to sur- 
round the solar orbit instead of intersecting it. This can- 
celled drawing had got in among a number of maps in a 
portfolio, where Eeymers must have seen it, as he copied 
the erroneous orbit of Mars in the diagram of his book. He 
therefore expressed his concurrence in the not very flatter- 
ing expression which Eothmann had applied to Eeymers 
Bar in a former letter. ■'^ 

It must, however, be said that this accusation of plagi- 
arism is founded on very slight evidence, and the verdict 
of posterity can only be " not proved." In his writings 
Eeymers has shown himself an able mathematician, and 
there is no reason whatever why he should not indepen- 
dently have arrived at a conclusion similar to the idea 
which Tycho conceived on the planetary motions. We 
shall afterwards see what a curious end this affair got, and 
how Tycho and Eothmann may have regretted that they 
had not let the hear alone. 

^ £piat. astr., pp. 149, 150. 



After the publication, or rather the completion, of the second 
volume of his book Tycho pushed on the preparation of the 
first volume on the new star, of which the printing began 
long before the manuscript was approaching completion. 
From many direct or indirect allusions to time in various 
places in the book, it appears that it was written in the 
years 1588 to 1592,^ and as Tycho had several times been 
inconvenienced by want of paper, he resolved to build a 
paper-mill on the south-western coast of the island, which 
could be driven by the water from the fish-ponds. This 
mill was finished in 1589 or 1590, and the same water- 
wheel which turned it could also be connected with a corn- 
mill and machinery for preparing skins.^ It was, however, 
by no means only the want of paper which delayed the 
completion of Tycho's book ; it had come to embrace 

1 See, e.g., Progym., i. pp. 34, 52, 102, 335, 559, 710, 721, 745. In the 
appendix written by Kepler it is stated that the book was written between 
1582 and 1592, but the printing cannot have commenced before 1588, and 
that the iirst chapter was written in 1588 is evident. 

2 In a letter to Rothmann (24th November 1 589) Tycho mentions the mill 
as having been for some time at work. The inscription on a slab in the wall 
of the mill is given slightly different by Resen., Inseript. Hafn., 1668, p. 335 
(Weistritz, !. p. 69), and in the DansJce Magazin, ii. p. 265 (Weistritz, ii. p. 
1 98) ; and according to the former it was begun in 1589 and completed in 
1590 ; according to the latter, commenced 1590, finished 1592. But the former 
dates must be correct, as they agree with Tycho's statement that the mill was 
at work in 1589 ; and in the meteorological diary we read under 22nd July 
1 590 : " Abiit Valentinus opere aggeris apud molendinum confeoto." In 
March 1590 the widow of Steen Bille was ordered to allow Tycho to cut down 
an oak in the wood at Heridsvad for use in the mill {D. Magazin, ii. 264). 



many branches of astronomy, and as the current observa- 
tions continued to reveal imperfections in ' the values of 
astronomical constants handed down from antiquity, Tycho 
was unwilling to finish the book and deprive himself of 
the power of inserting in it further results of his work. 
The book was never issued in a complete, state in his life- 
time ; only a very few friends or correspondents received 
incomplete copies or portions of the book ; and after Tycho's 
death an important section (32 pp.), separately paged, was 
inserted at the end of the first chapter. When completed, 
the book numbered more than 900 pages, divided into three 
parts and a " conclusion ; " and it bears many traces of 
having been both written and printed in the course of many 
years, succeeding sheets frequently before preceding ones. 
The first chapter deals with the apparent motion of the sun, 
the length of the year, the elements of the solar orbit, re- 
fraction, and gives tables for the motion of the sun. As 
there were a few pages to spare (the second chapter having 
been printed and paged first), Tycho determined to devote 
them to the lunar theory, though this had nothing to do with 
the determination of star places, and was not even mentioned 
in the title of the chapter ; and as this subject grew in 
importance and difficulty, it eventually delayed the pub- 
lication of the volume considerably. The second chapter 
describes the methods of determining the places of stars, 
investigates the amount of precession, and contains Tycho's 
own catalogue of star places.-^ This finishes the first part 
of the book, and as we shall examine in our last chapter 
the various subjects dealt with, we may pass to the second 
part of Tycho's book, which is devoted to his own observa- 
tions of the star of 1572. 

1 The Catalogue was printed after the succeeding sheets, and the sheets 
KK. and LL. are therefore double ones, as the Catalogue filled more space 
than anticipated. 


The tliird chapter describes the appearance of the star, 
the gradual fading of its light, the variation of colour ; how 
it was seen by carriers, sailors, and similar people, a good 
while before the astronomers in their chimney-comers heard 
of it ; then branches off into a mythological account of 
Queen Cassiopea, and gives a map of the constellation with 
the star in it. Tycho refers to the Aristotelean idea of the 
unchangeable nature of the heavens, and to the star of Hip- 
parchus, which he believes to have been similar to his own 
star, and then to that of the Magi, which he says could not 
have been a star in the heavens, since it showed the way to 
a particular town, and even to a house, and was only seen 
by the wise men. He therefore summarily dismisses the 
idea that the star in Cassiopea should signify the return of 
Christ. Lastly, he mentions the stars said by Cyprianus 
Leovitius to have appeared in the years 945 and 1264. 
All these subjects we have dealt with in sufficient detail in 
the chapter on the new star, where the book of which we 
are now summarising the contents is frequently quoted. 

In the fourth chapter are given descriptions and illustra- 
tions of the sextant with which he observed the star, and 
of the great quadrant at Augsburg. This chapter also con- 
tains the measured distance of the new star from twelve 
stars in Cassiopea, the distances iTvter se of most of these 
stars (from observations made at Hveen in i 578 and 1583), 
and a number of observations made with the Augsburg 
quadrant. As this instrument was designed and con- 
structed by Tycho, he naturally wished to prove its ex- 
cellence, and inserted a number of observed declinations 
of circnmpolar stars (which give values for the latitude 
of Goggingen agreeing inter se within a minute), and the 
declinations of six zodiacal stars in equally good accordance 
with the results obtained at Hveen. 

In the fifth chapter the co-ordinates of the star both 


with regard to the ecliptic and the equator are computed 
from its distance from the other stars in Cassiopea and the 
places of these stars as observed at Hveen. Seven different 
combinationa give results of which the extremes differ only 
about half a minute.""" Tycho also gives the places of the 
twelve comparison stars according to Alphonso and Coper- 
nicus (i.e., Ptolemy), which differ in many cases upwards of 
a degree from his own. He then turns in the sixth chapter 
to the question as to where the star was situated in space, 
and proves in four ways that it was far beyond the planets, 
" in the eighth sphere." First, the shape, light, continual 
twinkling, immovability, daily revolution like the fixed stars, 
and its having lasted more than a year, prove that it was 
not a comet. Secondly, it had no parallax, as the distance 
from the pole and from neighbouring stars remained i"in- 
altered during the daily revolution, while the polar distance 
would have varied i° 5' if the star had been as near as the 
moon, 2' 5 2" if as near as the sun, and 1 6" if at the distance 
of Saturn, with smaller variations in the distances from the 
other stars.^ Here he not only gives this indication of liis 
idea of the distance of the planets, but also shortly alludes 
to his system of the world. He remarks that if the star 
was situated in the sphere of Saturn, and if we adopt the 
annual motion of the earth according to Copernicus, the 
star would in a year appear to mov^ backwards and forwards 
(i.e., have an annual parallax) to the extent of about ten 
degrees, so that even followers of Copernicus must admit 
that the star was far beyond Saturn. The third proof of 
the great distance of the star is, that the meridian alti- 

1 The result adopted by Tycho is for 1573, AR 0° 26' 24", Deol. 61° 46' 45", 
while Argelander found 0° 28' 6" and 61° 46' 23" from a recomputation of the 
distance measures, using Bessel'-s and Bradley's star places. Astr. Nachr., 
Ixii. No. 1482. 

^ On p. 414 he refers to the diflficulty of finding the parallaxes of the outer 
planets, and how Mars was nearer than the sun. See above, p. 179. 


tudes gave the same latitude (for Heridsvad and Goggingen) 
as other stars gave ; and the fourth is, that observations at 
far-distant places gave results in good accordance inter se, 
as, for instance, his own and those of Munosius at Valencia. 
As Tycho has so often referred to the parallax of the moon, 
he verifies at the end of this chapter the value of Coperni- 
cus by computing the lunar parallax from six observations, 
three on the meridian and three at the nonagesimal point, 
where there is no parallax in longitude. 

In tho seventh and last chapter of the second part of the 
book Tycho attempts to calculate the diameter of the new 
star. He first recounts the crude ideas of his predecessors 
as to the diameters of the planets and fixed stars, on which 
he did not improve very much himself. He did not, however, 
place all the fixed stars at the same distance just beyond 
the orbit of Saturn, and he suggested that the fainter stars 
are probably at a far greater distance than the brighter 
ones, though even if they were at the same distance it 
would not follow that all the stars which we consider as 
belonging to one magnitude were equal in size, as Sirius 
and Vega are much larger than Aldebaran, which again is 
larger than E.egulus.'' The apparent diameter of the sun 
Tycho had, in 1591, measured " through a canal 3 2 feet 
long," and in this way he found that at the apogee the 
diameter was barely 30', and' at the perigee slightly above 
3 2'." The instrument was, according to Kepler, a screen 
on which the image of the sun fell through a small opening, 
and the " canal " must have been added merely to exclude 
stray light.^ The diameter of the moon Tycho generally 

» Progym., p. 470. 

' Ibid., p. 471. Historia Coelestis, p. 475 et seq. Tyoho's mean diameter 
31' is exactly i' too small, and the difference between apogee and perigee is 
only 1', as Kepler already found, 

^ Ad Vitdl. Parol., cap. xi. ; Opera omnia, ii. pp. 343-44, where Kepler quotes 


determined by observing the difference of declination of 
the upper and lower limb ; he adopts the mean diameter 
33'. With these data he now calculates the real diameters 
of the sun and moon, making use of the old value of the 
solar parallax of 3', which neither Copernicus nor he thought 
of discarding. The distance of the sun being 1 1 5 o semi- 
diameters of the earth, the semi-diameter of the sun will be 
5.2 times that of the earth, and similarly the distance of the 
moon is 60 and its semi-diameter 0.29. For the planets 
he assumes apparent diameters from 2' to 3', and calculates 
from these their diameters and volumes in parts of those 
of the earth.-*- For the fixed stars Tycho assumes smaller 
apparent diameters than other astronomers did before the 
invention of the telescope.^ With regard to the distance 
of the stars, he believes the greatest distance of Saturn to 
be 12,300 semidiameters of the earth (to arrive at which he 
sketches the theory of Saturn as mentioned above ®) ; and 
as he does not believe that there is a great void between 
the orbit of Saturn and the fixed stars, he places these at 

some observations made at Hveeii in March and June 1578, giving 30' 35" 
and 29' 53". About tile diopters of Hipparchus, see Halma's preface to the 
Almer/ist, vol. ii. p. Iviii. 

^ The diameters of the planets are measured by pointing with the armilte 
or a quadrant alternately to the upper and lower edge of the planet. See, 
e.g., Bistoria Coelestis, p. 4Z9, for a number of measures of Saturn. The 
diameters assumed are {Prog., pp. 475-76) ; — 

Mercury 2' 10" at mean distance, 1,150 

Yenus 3' 15" „ „ 1,150 

Mars I' 40" „ „ 1,745 

Jupiter 2' 45" „ „ 3,990 

Saturn i' 50" „ „ 10,550 

^ First mag. diameter 120", second 90", third 65", fourth 45", fifth "o" 

sixth 20" (ibid., pp. 481-82). Magini took the stars of the first mag. to 

be 10' in diameter ; Kepler made the diameter of Sirius 4' [Opera, ii. p. 676) ■ 

the Persian author of the Ayeen Akhery put the diameter of sturs of the first 

mag. = 7' (Delambre, Moyen Age, p. 238), so that Tycho's estimates were more 

reasonable than any of these. 

' The ratio of the semidiameters of the deferent of Saturn and of the solar 
orbit he borrows from Copernicus. Compare above, p. 181, footnote ^ 


a distance of about 14,000, and the new star at least at 
13,000 semidiameters. The apparent diameter of the new- 
star at its first appearance he estimated at 3 A', and its real 
diameter must therefore have been 7g times that of the 
earth, or somewhat greater than that of the sun. He does 
not think that the diminution of light was caused by 
the star having moved away from us in a straight line, 
partly because no celestial body moves in a . straight line, 
partly because it would, when about to disappear, have been 
at the incredible distance of 300,000 semidiameters of the 
earth. The star must actually have decreased in size, so 
that it at the end of the year 1573 was about equal to the 
earth in size. 

This finishes what Tycho has himself found by observa- 
tion and speculation concerning the star of Cassiopea, and 
he next devotes the third part of his book, 300 pages, 
to an examination of the writings of other astronomers or 
authors about the star. First he discusses in Chapter VIII. 
the observations of those who could not find any parallax 
(the last book considered being his own little book of 
I 573) of which he reprints the greater part, omitting the 
astrological predictions) ; next he deals in Chapter IX. with 
those authors who thought they had found some parallax, 
but who did not place the star within the lunar orbit ; and 
lastly, he deals with the writers " who have not brought out 
anything solid or important, and either maintained that the 
star was not new or that it was a comet or a sublunary 
meteor." His remarks are often written in a sarcastic 
style, with puns or play upon words, by which he perhaps 
meant to relieve the dulness of this far too lengthy part of 
the book. We have above, in our third chapter, given the 
reader some idea of these various classes of writers, and 
need not, therefore, here enter into further details about 
these chapters of Tycho's book. 


Finally, the " Conclusion" of the volume (pp. 787-816) 
gives first a rapid summary of the contents of the book, and 
then deals with two questions not yet touched upon, the 
physical nature of the new star and the astrological effect 
and signification, which the author did not wish to enter on 
in the body of the work, "as these matters are not subject 
to the senses, nor to any geometrical demonstration, but 
can only be speculated on." As to the nature of the star, 
Tycho considers that it was formed of " celestial matter," 
not differing from that of which the other stars are com- 
posed, except that it was not of such perfection or solid 
composition as in the stars of permanent duration. It was 
therefore gradually dissolved and dwindled away. It became 
visible to us because it was illuminated by the sun, and the 
matter of which it was formed was taken from the Milky 
Way, close to the edge of which the star was situated, and 
in which Tycho believed he could now see a gap or hole 
which had not been there before. This idea may to the 
modern reader seem absurd, but it should be remembered 
that the telescope had not yet revealed the true nature of 
the Milky Way, and Tycho's ideas about the latter were at 
all events a great advance from those of Aristotle (which 
he sharply attacks), according to which the Milky Way 
was merely an atmospheric agglomeration of stellar matter. 
With. Regard to the other question, the astrological signi- 
fication of the star, Tycho had evidently considered it a good 
deal since he wrote his little book in 1573, and he does 
not on this occasion merely express himself in very general 
terms, but gives his opinion with more decision. As his 
prediction attracted a good, deal of attention, particularly 
later when it seemed to have been fulfilled, it is worth 
while to give a short summary of it. 

As the star of Hipparchus announced the extinction of 
the Greek ascendency and the rise of the Roman empire, 



so the star of 1572 is the forerunner of vast changes, not 
only in politics, but also in religious affairs, for the star was 
situated close to the equinoctial colure, which by astrologers 
is supposed to have something to do with religious matters.'' 
And as the star first shone with Jovial and clear light, and 
afterwards with Martial and ruddy light, the effect will first 
be peaceful and favourable, but afterwards become violent 
and tumultuous. And the religions which are full of 
" Jovial " splendour and pomp, after having for a long lime 
dazzled ignorant people by their external magnificence and 
more than Pharisaic formalism, will, like that pseudo-star, 
fade and disappear. Though the star was so near the 
■equinoctial colure that it nearly touched it with its rays, it 
was quite within the vernal quadrant, and it announces that 
some great light is at hand, just as the sun when past the 
vernal equinox conquers the darkness of night. And as 
the star was visible over most of the earth, so the effects of 
it will be felt over the greater part of the globe, though 
the northern hemisphere will be especially affected. With 
regard to the time when the influence of the star will begin 
to be felt, this will be nine years after the great conjunction 
of pla,nets in April 1583, in the 21st degree of Pisces (be- 
cause the direction of this and the star along the equator 
is 9°), or in other words, in 1592, and those who were born 
when the star appeared will about that time enter man's 
estate, and be ready for the great enterprise for which they 
are ordained. But if we take the direction along the 
zodiac, we find forty-eight years, after the lapse of which 
period the effect of the star will become strongest, and will 
last for some years, until 1632 or about that time, when 
the effect of the fiery trigon (which the star announced) 
will also be felt. The conjunction of 1583 concluded a 
cycle of planetary conjunctions, the seventh since the 

^ Pisces was supposed to be the sign of Palestine. 


creation of the world.^ The first cycle ended at the time 
of Enoch, the second at the deluge, the third at the exodus 
from Egypt, the fourth at the time of the kings of Israel, 
the fifth at the time of Christ when the Roman empire was 
at its height, the sixth when the empire arose in the 
western world under Charlemagne, and the seventh and 
sabbath-like one was now coming. And as the first, third, 
and fifth " restitution " had been salutary to the world, the 
seventh, which had a particularly uneven number, will in- 
augurate a very happy state of things, a peaceful and quiet 
age such as that foretold by the prophets Isaiah (ch. xi.) 
and Micah (ch. iv.), when the lion shall eat straw like the 
ox, and the sucking child shall play on the hole of the asp, 
&c. As to the place on the earth from which this change 
will arise, it will be the one in the Zenith of which the star 
was at its first appearance, which Tycho assumes to have 
been at the time of the New Moon previous to the nth 
November, when he noticed the star.^ The star was then 
on the meridian of places about 1 6° east of Uraniborg and 
in the Zenith of a place with north latitude 6 if". This 
fixes the ominous spot " in Russia or Moschovia where it 
joins the north-east part of Finland." Having devoted so 
much space to this matter, I must pass over the way in 
which Tycho finds Moschovia pointed out in the Prophets, 
the Revelation, and a certain ancient prophecy of Sibylla 
Tiburtina, found in 1520 in Switzerland. 

That Tycho when writing of the religion distinguished 
by pomp and splendour which was soon to disappear was 
thinking of the Roman Catholic persuasion is beyond a 

^ " Septima hsc est trigonorum in integrum ab Orbe condito restitutio." 
■About tile trigoni see above, p. 49, footnote. Tile conjunction of Jupiter 
and Saturn in Sagittarius in December 1603 commenced a new cycle with a 
fiery trigon. 

" See above, p. 50. Tycho now {Proffym,, p. 809) gives the time of New 
Moon as 7h. 3ifm. p.m., 


doubt, and it is curious tliat the book in whicli we read 
tbis, though printed in Denmark, should eventually come 
to be published at Prague (where the religious war which 
he foretold raged furiously less than twenty years after his 
death) and was dedicated to the Roman Emperor ! But it 
is more curious still that some of his other predictions 
seem to be fulfilled in the person of Gustavus Adolphus, 
the greatest champion of Protestantism in' the seventeenth 
century. He was born in 1594 (only two years after the 
influence of the star should begin to be felt), and his glory 
was greatest in the year in which he fell, 1632, the very 
year mentioned by Tycho. He certainly was not born in 
Finland (for it is Finland and not the adjoining part of 
Russia which is indicated by 16° east of Uraniborg and 62° 
Latitude), but in Stockholm ; but Finland was still a province 
of Sweden, and the yellow Finnish regiments were con- 
spicuous for their bravery on many a blood-stained battle- 
field in Germany. No wonder that many contemporaries 
of Gustavus Adolphus were startled by these coincidences, 
and that the concluding part of Tycho's book was translated 
into several languages.^ But the star had a truer mission 
than that of announcing the arrival of an impossible golden 
age. It. roused to unwearied exertions a great astronomer, 
it caused him to renew astronomy in all its branches by 
showing the world how little it knew about the heavens ; his 
work became the foundation on which Kepler and Newton 

^ I possess an English translation which seems to be very scarce : " Learned 
Tico Brahoe his astronomicall Coniectur of the new and much Admired * which 
Appered in the year 1572," London, 1632, 26 pp. text, 5 pp. dedication ("To 
the High and Mighty Emperour Rvdolphvs the IL The Preface of the Heyres 
to Tycho Brahe"), and 2 pp. of epigrams by the translator and James VI. I 
have seen another copy in whicli there was a portrait of Gustavus Adolphus. 
Lalande has a German translation also printed in 1632, and there is a Dutch 
one printed at Goude in 1648 (" Generale Pritgnosticatie van het jaer 1572 tut 
desen tegenwoordigen Jare, alles in Latijn beschreveu van Ticho Brahe ") in 
the library of Triu. Coll., Dublin. 


built their glorious edifice, and the star of Cassiopea started 
astronomical science on the brilliant career which it has 
pursued ever since, and swept away the mist that obscured 
the true system of the world. As Kepler truly said, " If 
that star did nothing else, at least it announced and pro- 
duced a great astronomer." ^ 

^ " Certe si nihil aliud stella ilia, magnum equidem astronomura significavit 
et progenuifc. " Tlie last words in Kepler's Appendix to tlie Progymnasmata. 



At the death of King Frederick II., in 1588, his eldest son, 
Prince Christian, who had been elected his successor, was 
only eleven years of age. The Queen claimed the right of 
governing the country during his minority, and asked the 
Privy Council if she had not in her husband's lifetiroe 
shown her love to the two kingdoms, and whether they 
could show cause why she should have forfeited the right 
of Dowager-Queens. But the powerful nobles were deter^ 
mined to take the reins into their own hands, and 
elected four Protectors from among the Privy Councillors 
— the Chancellor, Niels Kaas ; the Chief of the Exchequer, 
Christopher Yalkendorf ; the Admiral Peder Munk ; and 
the Governor of Jutland, Jorgen Rosenkrands. In order to 
keep their power as long as possible, it was decided that the 
minority should last till the Prince was twenty years of 
age. The quiet and careful education of the young King- 
Elect, which his father had planned, was continued, and the 
Government of the Protectors was on the whole well and 
ably conducted. To Tycho Brahe it was of great importance 
that the Chancellor Kaas was a member of the Government, 
as the precarious tenure by which he held all his endowments 
and pensions made it a vital matter for him to have firm 
friends among those at the head of affairs. Probably with 
a view to ascertain how far the new Government was 
friendly to him, Tycho in the spring of 1588 addressed 

a memorial to the young King in which he showed 



that he not only had spent his various pensions and the 
income from his hereditary estate on his buildings and 
works at Hveen, but had incurred a debt of 6000 Daler 
(;^l36o), and he begged that the King would indemnify 
him for this loss, as he had spent the money according 
to the desire of the late King and for the honour of 
the country. On the 8th July, Kaas and Eosenkrands 
paid Tycho a visit at Hveen, and probably by their advice 
the young King, on the 1 2th July, with the sanction of 
the Privy Council, granted the said sum of 6000 Daler to 
Tycho, 2000 to be paid by the Treasury and 4000 from 
the Crown revenue of the former Dueholm monastery in 
Jutland. The money was paid on the 1 4th December follow- 
ing, 2000 from the Sound dues and 4000 from Dueholm.'' 
In addition to this proof of the continued favour of the 
Government, the Protectors on the 23rd August issued a de- 
claration promising to keep the buildings at Hveen in repair 
at the public expense, and on the expiration of the King's 
minority to advise him to fix a certain annual endowment 
for the continuance of the astronomical work there by some 
fit person of Tycho's own family, or, failing such, by some 
suitable person of Danish nobility or by some other native.^ 
In the following year, on the 17th July 1589, a new 
declaration to the same effect and very much in the same 
words was drawn up and signed and sealed, -not only by 
the four Protectors, but by all the members of the Council, 
fourteen in number.' 

Though these declarations were very reassuring to Tycho, 
he seems to have thought that the young King might 
possibly in future years not consider himself bound by 
them, for in March 1590 he procured a letter from the 

' Danske Magazin, ii. p. 249, 253 (Weistritz, ii. 175 and 182). 
» Ibid., p. 250 (W., p. 177). 
" Ibid., p. 260 (W., p. 192). 


Queen "stating that slie perfectly remembered to have heard 
King Frederick, some time before his death, express his 
intention of appointing one of Tycho's children to succeed 
him at Hveen, if one should be found skilful in the astro- 
nomical art.^ Tycho does not appear to have made any 
use of this letter in after years, perhaps because neither 
of his two sons showed any taste for astronomy. 

For the present, at any rate, Tycho's position was secured 
by the new Government, and we have already seen that the 
grant of the Norwegian estate was renewed in June 1589. 
In this year he received another mark of the friendly 
feelings of the Government, as a letter from the young king 
to the burgomasters and Corporation of Copenhagen (dated 
Copenhagen the 13th March 1589) ordered them to lend 
Tycho Brahe a stone tower next the rampart, " and a small 
piece of the rampart up to his paling," as he intended to 
erect a building on the tower for astronomical use, where 
he wanted to keep some instruments for the use of some 
people who might reside there and practise with them. He 
was, however, to give up the tower and rampart whenever 
they might be required for the defence of the city.^ This 
part of the rampart was doubtless close to a house which he 
is known to have owned in the Farvergade, in the south- 
west part of Copenhagen, perhaps at the corner where the 
street (until a few years ago) adjoined the rampart, as the 
latter is said to "reach to his paling." On the 25th of 
March following the king furthermore gave to Tycho and 
his heirs for ever two empty houses next his own, on con- 
dition that he should build another house for the dyer who 

^ Breve og A UstyJcJcer angaaende Tyge Brake og lians Slcegtninge. Sam- 
lede a£ F. R. Friis, Kjobenhavn, 1875, p. I. Trom the Queen's letter-book 
in the Royal archives. It appears from two other letters that the Queen had 
lent Tyoho :ooo Daler, which he was to pay back at Michaelmas 1 590. 

'' G. F. Lassen, Docwmenter og Actstykker tU Kjobenhavn' s Befaestnings 
Historic, Copenhagen, 1855, p. iii. 


had carried on business in one of ttose wHcli Tyclio got. 
Though he frequently went to Copenhagen (as may be seen 
by the Meteorological Diary), nothing is known about his 
domestic arrangements there, nor do we know whether he 
really kept students or pupils. No observations were made 
at Copenhagen. 

At Hveen the life and work continued as in previous 
years, and Tycho was still honoured and feted by both com- 
patriots and foreigners. Among his nearer friends, Vedel 
and Erik Lange paid him occasional visits, and early in 
1590 the latter became engaged to Tycho's youngest sister, 
Sophia, who was a very frequent guest at Uraniborg, and 
who after Steen Bille's death (1586) was the only one of 
Tycho's relations who was capable of appreciating the work 
carried on there. ^ At the age of nineteen or twenty she 
had been married to Otto Thott of Eriksholm, in Scania, 
who died in 1588, leaving an only child, Tage Thott, 
daring whose minority the young widow managed the 
property of Eriksholm. Here she devoted her leisure hours 
partly to horticulture (in which she must have excelled, 
since Rothmann, who paid her a visit during his stay in 
Denmark, thought her garden worthy of special praise to 
the Landgrave), partly to chemistry and medicine (which 
latter she made use of to relieve the poor), and especially 
to judicial astrology, to which she was greatly devoted, so 
that she is said to have always carried a book about with 
her in which the horoscopes of her friends were entered. 
She had several times met Erik Lange at Uraniborg, where 
he probably came to consult Tycho on matters relating 
to alchemy, on which 'pursuit he squandered his fortune. 

1 DansJce Magazin, ii. p. 254 (Weistritz, ii. p. 183), where also is given 
Tycho's acknowledgmeat of his being bound to provide the dyer with a new 

'' About her observation of the lunar eclipse of 1573, see above p. 73. 


The matcli was not a brilliant one for her, though Lange 
was her equal as regards birth, but in searching for the 
philosopher's stone he had become greatly indebted, and in 
order to escape his creditors he left the country in 1591, 
hoping perhaps abroad to be more successful in the gold- 
making line than he had been at home. It is needless to 
say' that he met with new disappointments, and Sophia and 
he were not united till 1602, six months after Tycho's 
death. ■*■ 

Sophia Brahe and her future husband were not the 
only guests at Uraniborg in the spring of 1590, at which 
time Tycho received his most distinguished visitor. King 
James VI. of Scotland. This monarch had several years 
before made overtures for the hand of Princess Elizabeth, 
the eldest daughter of Frederick II. His envoy, Peter 
Young, had, however, produced powers so limited, or had 
conducted the negotiations in so lukewarm a manner (it is 
supposed at the instigation of Queen Elizabeth), that the 
Danish king did not believe the wooer to be in earnest, and 
promised his eldest daughter to the Duke of Brunswick. 
Not discouraged by this failure, and yielding to the loudly 
expressed wish of the Scotch nation to see the king married 
soon, James solicited the hand of King Frederick's second 
daughter, Anne. The Earl Marshal, Lord Keith, was sent 
to Denmark in 1589, and the marriage was celebrated at 
Kronborg Castle by procuration. The bride set out for 
Scotland in September, escorted by a Danish fleet of four- 
teen vessels, but a storm obliged the fleet to seek shelter at 

' Danske, Magazin, iii. (1747), p. 12 et seq. During Lange's absence abroad 
Sophia Brahe sent him a long letter in Latin verses, which is printed in 
Resenii Inscriptiones liafnienses (1668), but from a very incorrect copy. 
There is a more correct copy in the Hofbibliothek at Vienna, printed in Breve 
og Actstylcker, pp. 6-25. The poem is most interesting from the numerous 
allusions to alchemy and astrology in it, but Sophia Brahe cannot have written 
it in Latin, to judge from what Tycho says of her attainments in a MS. note, 
also in the Hofbibliothek (ibid., pp. 160-161). 


Oslo in Norway, and James was informed that it was not 
likely to put to sea again for some months. Vexed at this 
new disappointment, he quickly made up his mind (not a 
very usual thing for him to do, but he was probably anxious 
to have the vexed question of the Orkney and Shetland Isles 
settled as soon as possible), and having, without communi- 
cating his intention to his Council, fitted out some ships, he 
started for Norway attended by the Chancellor, Sir John 
Maitland, and a numerous suite. He arrived at Oslo in 
November, and the marriage was solemnised at Aggershus 
Castle on the 24th of that month by his own chaplain, 
David Lyndsay. The timid monarch did not care to face 
the boisterous North Sea a second time in winter, and re- 
mained in Norway for some time, until he accepted the 
invitation of the Danish Government and set sail for Kron- 
borg, where he arrived with his bride on the 20th January 
1590. A month after he went to .Copenhagen, where the 
usual festivities were held in his honour ; but James did 
not neglect the opportunity of enjoying the conversation of 
learned men, and even went to see the theologian Hemming- 
sen at Eoskilde. It is natural that he should wish to see 
the spot to which the eyes of all the learned men of Europe 
were directed, and on the 20th March he paid a visit to 
Tycho Brahe at Hveen, arriving at eight o'clock in the 
morning and remaining till three P.M.^ King James was 
particularly pleased to see in the library at Uraniborg the por- 
trait of his former tutor, George Buchanan, which had been 
presented to Tycho by Peter Young, who had once taught 
James to spell, and had afterwards several times been sent 
to Denmark on various missions. The learned king and 
the astronomer had thus more than one interest in common, 
and it is easy to imagine the delight the former must have 

^ Meteorological diary : "Hex Sohotise venit mane H. 8, abiit H. 3." 
^ He was now the king's almoner. 


felt while conversing with his host. To show how gratified 
he was with his reception, he wrote at Uraniborg (whether 
it was in a " visitors' book " does not appear) : 

Est nobilis ira Leonis 
Parcere subjeetis et debellare superbos. 
Jacobus Eex.^ 

Why he wrote these particular lines is not easy to under- 
stand, but perhaps he considered them emblematic of 
" kingcraft." " Maitland also tried his hand at Latin verse- 
making, expressing his admiration of the house of the 
Muses. The king is said to have discussed the Copernican 
system and other matters with Tycho, and was doubtless 
equally proud of his own exhibition of learning and pleased 
with the hospitable reception he had met with. He readily 
promised Tycho copyright in Scotland for his writings 
for thirty years, and sent him this three years later, ex- 
pressing in the document the pleasure it had given him to 
converse with Tycho and learn with his own eyes and ears 
things which still delighted his mind. Two Latin epigrams 
accompanied the document and are printed with it at the 
beginning of Tycho's Progymnasmata.^ King James is also 
said to have presented Tycho with two tine English mastiflfa 
before his departure. Various members of his suite paid 
visits to Hveen during the time between the king's visit 
and his final departure from Denmark, which took place on 
the 2 1 st April.* 

' Danske Magazin, ii. p. 266 (Weistritz, ii. p. 200). 

^ These lines seem to have been a standing dish with King James, for 
according to Horace Marryat (A Residence in JutLand, the DanUh Ides and 
Copenhagen, London, i860, voL i. p. 306) he also wrote them in a hymn-book 
belonging to Kamel, tutor to the young King Christian IV. 

' Also in Gassendi, p. 106. 

■* I'pist. astron., p. 175: "Exinde quasi quotidianos hospites habuerim." 
Meteor, diary, April 21 : "Rex ScotiEe circiter horam 7 P.M. Helsingora cum 
Regina sua et comitatu in reguum per mare discessit, Navali regis comitata 


Two days before his departure King James had at Kron- 
borg assisted at the nuptials of the lady he had first wooed 
with Henry Julius, Duke of Brunswick-Wolfenbiittel. Of 
course the Duke had also to be taken over to Hveen to see 
the wonders there, which he and his suite did on the 4th 
May ; but this visit does not appear to have been as pleasant 
to Tycho as that of King James. The Duke took a fancy 
to the little revolving statue of Mercury which stood on 
the roof of the central room of Stjerneborg, and thought it 
would be a pretty toy to take home with him. Tycho had 
to give him permission to take it away with him, when the 
Duke had promised to send him an exact copy of it, which 
promise he never took the trouble to fulfil, though Tycho 
sent him several reminders.'' Gassendi tells a curious in- 
cident of this visit, which he had heard from Janszoon 
Blaev. At table the Duke remarked that it was getting 
late and he would have to take his leave, but Tycho, who 
perhaps was still annoyed at the loss of the statue, said in 
a joking way that it was his right to give the signal for 
breaking up. The Duke took ofience at this and walked 
off towards the shore without taking leave, and when Tycho, 
who had first remained at table, after a little while followed 
him and offered him a stirrup-cup, the Duke turned away 
and continued his walk. Upon which Tycho let him go, 
and returned home without troubling himself more about 
his guest.^ This may be only gossip, but Tycho was cer- 
tainly haughty and self-sufficient enough to have behaved 
in this manner even to the king's brother-in-law, and he 
probably made himself more than one powerful enemy by 
his overbearing manner. 

A more welcome visitor arrived three months after this 
event in the person of the Landgrave's astronomer, Chris- 

^ Tycho tells this himself in Epist., p. 256. 
^ Gassendi, p. 196. 


topher Rothmann, who came to Hveen on the 1st August 
and stayed with Tycho till the I st September. He seems to 
have been a somewhat peculiar character, and to have taken 
a rather unfair advantage of the great modesty and retiring 
disposition of his colleague, Biirgi, to push himself into the 
foreground, if not actually to try to shine with borrowed 
plumes.'' In a letter of which he was the bearer, the Land- 
grave wrote that Rothmann had been in bad health for 
some time, and imagined that a little travelling and change 
of air would do him good. " But he has a head of his own, 
for which he every year buys a hat of his own, so we must 
leave him to himself; but we should be sorry if anything 
happened to him, for he is ingenious and a fine, learned 
fellow." ^ Tycho and he had now been in regular corre- 
spondence for about four years, and had in their letters 
entered very fiilly into the methods of observing used at 
Hveen and at Cassel, and the advantages or difficulties of 
the Copernican system. They had discussed the frequently 
observed " chasmata " or aurorse (which Tycho took to be 
sulphurous exhalations ignited in the air, and not clouds 
illuminated by the sun, as the latter was too far below the 
horizon in winter') ; they had exchanged ideas about the 
celestial space, which Tycho did not believe to be filled with 
air, as this would produce a sound when the planets moved 
through it (which Rothmann denied) ; about the amount of 
refraction and the duration of twilight, for which Rothmann 
assumed a depression of the sun equal to 24°, while Tycho 
found 16° to 17°,* and on any other subject which their 
work might suggest. Rothmann had prepared for publica- 

^ R. Wolf, Asir. Mittheilungen, xxxii. p. 66. 

^ Epist. astr., p. 182. 

^ Epist., p. 162. In his Handhuch der Matliematik, Astronomie, <fcc., ii. 
P- 337i R- Wolf states that Tycho and Rothmann had seen the zodiacal 
light ; but I have not been able to find anything which looks like an observa- 
tion of this. ■> Epist., pp. 139-140. 


tion several treatises, none of which have ever been printed, 
among which was one on trigonometry, which he had thought 
of dedicating to King Frederick II., one on the Copernican 
system, which he suppressed when he saw how badly the 
Prutenic tables agreed with the observations,^ and a treatise 
on spherical and practical astronomy, which is still preserved 
in MS. at Cassel.^ 

Tycho and his guest must have had plenty of subjects 
for conversation, and the host no doubt did his best to 
entertain the man with whom he had for years exchanged 
ideas, though they had never yet met. It appears from 
the diary that several foreign visitors came and went during 
Eothmann's stay at Hveen, and these as well as the above- 
mentioned trip to Scania to see Sophia Brahe and her 
garden lent variety to the visit. There were even some 
fine aurorge to be looked at and discussed. The many 
interesting objects to be seen at Hveen, and the scenery, so 
charming in summer-time, ought to have made Eothmann's 
stay at Uraniborg very pleasant ; but unluckily Tycho seems 
to have belaboured him with arguments against the Coper- 
nican system which must have become somewhat tiresome 
in the end. In a lengthy note which Tycho has inserted 
among his printed letters,^ he states that during the weeks 
he had Eothmann with him he pleaded his cause with this 
generally very obstinate man so well, that Eothmann began 
to waver, and finally declared himself convinced, and assured 
Tycho that he had only held to his opinion for the sake of 
argument ; he even added that he had not published, and 
never would publish, anything in that direction. Doubtless 
Eothmann was glad to end a dispute which could lead to 
nothing, and both these skilful observers knew well that 

^ Ibid., pp. 89-90. 

^ R. Wolf, Astr. Mitth., xlv., where there is a r4sum6 of the contents. 

2 Efist. astr., pp. 188-192. 


there was a great deal of work to he done yet ere the true 
system of the world could be indisputably proved. In the 
note already alluded to Tycho sets forth the arguments 
which he had made use of. These refer only to the rota- 
tion of the earth, as he thought the two other motions 
would be untenable when that was disproved. He main- 
tains that though the thin and subtle air might follow the 
rotatory motion, a heavy falling body would not, and if two 
projectiles were shot out with equal force, one towards the 
east and the other towards the west, he was sure they would 
go equally far, and thus prove that the earth was stationary. 
The enormous velocity with which the eighth sphere revolves 
in twenty-four hours he considers a proof of the wisdom and 
power of God ; and as motion is more noble than rest, it is 
natural that the ethereal world should be ia motion and 
the lower and coarser earth at rest, and this idea he dwells 
on at some length. 

Rothmann left Tycho on the 1st September 1590, osten- 
sibly to return to Cassel ; but whatever the reason may have 
been, he went instead to his native place, Bemburg in Anhalt. 
After a long silence he wrote once more to Tycho ia Septem- 
ber 1594, but his letter was only a short one, complain- 
ing greatly of his health and inquiring why Tycho's book 
on the comet of 1577 had not yet been published. Tycho 
wrote him in January 1595a very long answer, which is 
almost entirely taken up by a defence of his book on the 
comet against the attack made on it by John Craig, for- 
merly Professor of Logic and Mathematics at Frankfurt on 
the Oder, and now Physician to the King of Scotland.^ 
Craig had in. 1588, through the intercession of a country- 
man (no doubt Liddel), obtained a copy of the book, and had 
written to Tycho trying to disprove the conclusion at which 

1 Chalmers' Gen. Bio'jraph. Dictionary, London, 1815, vol. xx. p. 243. Tycho 
does not mention his name. 


the latter had arrived, that the comet was far beyond the 
moon. Tycho had in reply taken the trouble to prepare a 
detailed " apology " for his book, and had sent it to Craig 
in 1589, and three years later the latter published a refuta- 
tion of Tycho's book, in which he (" nee tarn scotice quam 
scoptice ") made a violent attack on all who would not follow 
Aristotle's doctrine about comets.-"- In this last letter to 
Eothmann, Tycho, in a needlessly prolix manner, defends his 
observations and results against this obscure writer, who, 
but for his attack on Tycho, would be quite unknown in the 
annals of science.^ 

Eothmann never returned to Oassel, and nothing further 
is known of him. He was still alive in i 599, when Tycho 
heard from him through a mutual acquaintance, and he 
must have died before 1608, when a theological pamphlet 
by him was published, which is designated as posthumous.^ 
At Cassel, where the astronomical work was carried on by 
Biirgi, his continued absence created much surprise, and 
the Landgrave and Tycho, in the letters which they fre- 
quently exchanged in 1591, repeatedly expressed their 
wonder at his disappearance. These letters are not like 
the earlier ones, almost entirely devoted to astronomy, 
though Tycho did not omit to tell the Landgrave that the 
printing of the first volume of his work was approaching 
completion, and that he had sho-wn Rothmann as much as 
was in type ; it was partly want of paper which delayed the 

' " Capnuraniffi restinctio seu cometarum in aethera sublimationis refutatio." 
Kepler began a refutation of Craig's book (Opera, i. p. 279), and Longo- 
niontanus also (Gassendi, p. 206), but neither were printed. 

^ Epist, pp. 284-304. Tycho's first Apologia of 1589 -was never published 
though Lalande in his Bihliographie (and following him Delambre) mentions 
it as printed at Uraniborg in 1591. Tycho might have treated Craig's attack 
with the same contempt with which he met Christmaun's attack on his solar 
theory, which he only answered by putting up in one of his rooms a picture 
of a dog barking at the moon, with the inscription "Nil moror nu^as." 
Gassendi, p. 119. 

^ R. Wolf, Geschichte der Astronomic, p. 274. 



finishing of the book. The Landgrave offered to inquire at 
Frankfurt whether there might be one or two papermakers 
there who might be willing to go to Hveen, but Tycho 
wrote back that he had already got one.-"- In February 
1 5 9 1 the Landgrave wrote that he had heard of an animal 
from Norway, taller than a stag, of which there were some 
at Copenhagen and ia the royal deer park at Frederiksborg, 
and he would like a drawing of it. Tycho answered that 
he did not know of any such animal, but some time ago a 
reindeer had been sent to Copenhagen from Norway, but 
had died during the summer ; he sent, however, a drawing 
of it. The Landgrave again wrote that he had also twice 
got a number of reindeer from Sweden, and they seemed 
to thrive well in winter, and could draw a sledge on the 
ice, but they died as soon as warm weather came on. Li 
his deer-park at Zapfenburg, the Landgrave had an elk 
since the previous autumn, and it skipped about well, and 
when he came driving in his little green carriage, the elk 
would run alongside like a dog. If Tycho could send him 
one or two tame ones, he would be very pleased. This 
Tycho promised to do, and added that he had himself had an 
elk on his estate in Scania, and had wanted to get it over 
to Hveen. » In the first instance the animal had been sent 
to Landskrona Castle, where Tycho's niece's husband kept 
it for some days, until unluckily the elk one day walked up 
the stairs into a room, where it drank so much strong beer, 
that it lost its footing when going down the stairs again 
and broke its leg, and died in consequence.") Tycho never 
succeeded in getting an elk for the Landgrave, nor in 
satisfying his curiosity concerning the gigantic animal called 
Orix, about which the Landgrave had first inquired.^ 

7ist. astr., pp. 198, 202, 205, 215. In 1592 Tycho was buying rags in 
Seeland for his paper-mill [Danslce Magazin, ii. 280). 

^ Epist. astr., pp. 195, 200, 201, 205, 210, 212, 214. In April 1592 the 
Landgrave wrote that he had got four elks from Sweden, but three o£ them 
had died, probably from eating too many rotten acorns (p. 269). 


Among other matters, the Landgrave inquired about the 
state of affairs in Denmark, and Tycho gave him the re- 
quired information in detail, telling him that the young 
king-elect was being carefully educated, and that there was 
every prospect of his walking in his father's footsteps ; that 
among the four protectors, the one of greatest influence 
was the Chancellor Kaas, a man conspicuous not only by 
his illustrious descent, but also by his experience, judgment, 
and prudence, while he was also a very well-read man, 
particularly in historical and political matters. If anything 
of special importance occurred, it was referred to the annual 
assembly of nobles. The form of government was thus an 
aristocratic one (which was not a bad one), until the king- 
elect should attain his majority.-^ In return, the Landgrave 
sent Tycho some abstracts from newspapers about the state 
of France, and gave it as his opinion (in the curious mix- 
ture of German and Latin in which he always wrote), 
" dass es misserimus status totius Europse ist." ^ 

As Eothmann did not return to Cassel, and the Land- 
grave, therefore, did not see the drawings and descriptions 
of the instruments at Hveen which he had collected during 
his stay there, Tycho caused his German amanuensis to 
prepare a description of all the instruments, twenty-eight in 
number, which was sent to the Landgrave, and afterwards 
was inserted in the printed volume of letters, together with 
a Latin translation, which is somewhat longer, and furnished 
with woodcuts of the buildings and a map of the island, as 
well as with copies of the versified inscriptions on various 
portraits in Tycho's collection. Tycho was still anxious to 
have good mechanics in his service, and wrote to the Land- 
grave in February 1592 that his goldsmith, Hans Crol, 
was dead,^ who had had charge of his instruments for many 

' Epist. astr., p. 199, translated in Weistritz, ii. p. 209. 

" Ibid., p. 210. ' He died on the 30th November 1591 (Diary). 


years, and had made several of them. He therefore in- 
quired if Biirgi knew of an able man who might succeed 
him. It so happened that Biirgi shortly afterwards had to 
go to Prague to present to the Emperor a mechanical repre- 
sentation of the motions of the planets, and the Landgrave 
promised that he should inquire about some goldsmith who 
was accustomed to instruments and clocks. Whether Tycho 
got such a man is not known.'' 

The Landgrave died at Cassel on the 25th August 1592, 
at the age of sixty. His son and successor, Maurice, did 
not share his father's taste for astronomy (though he con- 
tinued to keep Biirgi in his service till 1603, when Biirgfi 
removed to Prague), but he was a man of literary tastes, 
and at Tycho 's request sent him a Latin poem for insertion 
in one of his publications, though he modestly disclaimed 
the poetical talent which had been attributed to him.^ 

Before Tycho lost his diligent correspondents at Cassel he 
had opened a literary intercourse with Giovanni Antonio 
Magini, from 1588 Professor of Mathematics at Bologna, a 
man who by his extensive correspondence and his literary 
activity gained a position of some importance in the history 
of science.^ We have already mentioned that Tycho's pupil, 
Gellius Sascerides, during his stay at Padua, sent Magioi a 
copy of the volume on the comet of 1577, and in 1590 
Magini wrote to Tycho thanking him for the welcome pre- 
sent, and expressing his approval of the new system of the 
world. Li this he could only have wished that the orbits 
of Mars and the sun had not intersected each other, though 

1 Eput., pp. 266 and 270. 

^ The verse is printed in Fpist., p. 281. Tycho wrote to Landgrave Maurice 
in December 1596, when he at last sent him the two elks which the late Land- 
grave had wished for so much (ibid., p. 305). 

2 Carteggio inedito di Tichone Brahe, Giovanni Keplero e di altri celebri 
astronomi e matematici dei secoli xvi. e xvii. con 6. A. JIagini, tratto dall' 
Archivio Malvezzi de' Medici in Bologna, pubblicato ed illustrate da A. Favaro. 
Bologna, 1S86, 8vo. 


this would be admissible if (as Gellius iiad told him) Tycho 
had found Mars in opposition to be nearer than the sun. 
He begged Tycho particularly to obserye Mars, as he sus- 
pected its excentricity to be variable and periodical, so that 
an equation to this effect should be introduced in the 
theory.'^ In reply, Tycho remarked that he had found this 
well-known difficulty not only in the theory of Mars, but in 
a lesser degree also in the theories of the other planets, and 
he wanted to observe the oppositions of Mars all round the 
zodiac. Ho also gave a short account of the reasons why 
he found it necessary to devise a new system. He would 
have sent Magini a copy of his star-catalogue, but the dis- 
tance was so great, and the difficulties of transit so con- 
siderable, that it might fall into wrong hands and somebody 
might publish it as his own.^ In conclusion, Tycho remarks 
that he had read in Magini's Tabulce Secundi Mobilis that 
geographical latitudes, since the days of Ptolemy, had in- 
creased more than a degree, but he does not believe it, as 
the latitude of Rome, according to Pliny, was 41° 54', 
while Regiomontanus found 42° 7' and 42° o'; likewise 
Pliny says that at Venice the gnomon and its shadow were 
of equal length at the time of equinox, which gives the 
latitude 45° 16', agreeing to the minute with Pitati's result ; 
also Pliny gave 44° 10' for Ancona, which was more than 
the modern value, 43° 20', instead of less, as had been 

Gellius spent about two years at Padua, where he was 
matriculated at the University in October 1589. In 
I 5 9 1 Magini had a sextant made from his description, and 

1 This letter is printed in Tycho's Astr. inst. Mechanica, fol. H., reprinted 
in Carteggio, p. 392. 

^ In February 159 1 Gellius wrote to Magini that Tycho had determined 
the places of 500 stars to within a minute of arc. Carteggio, p. 202. 

^ Carteggio, p. 403. It was Domenico Maria Novara (whose lectures Coper- 
nicus had attended) who had suggested that the latitudes had increased. 


they observed Mars with it together on some evenings in 
June and July, as Tycho had called Magini's attention to 
the singularly favourable opposition.'^ Magini wrote to 
Tycho that he was going to get a large quadrant and a 
radius (cross-staff) made with sights like Tycho's. He 
added that he could not procure for Tycho the copyright of 
his books in the Venetian dominions, as they had not been 
printed there. ^ In the following year Magini dedicated to 
Tycho a book on the extraction of square root, but the copy 
sent to Denmark never reached its destination, and Tycho 
did not see the book till five years later, when he came across 
another copy and reprinted the dedication in his Mechanica. 
In 1592, the year in which Tycho wrote the concluding 
part of his book on the new star, an event occurred which 
seemed to augur well for his future. The young king- 
elect, then fifteen years «of age, paid a visit to Hveen on 
the 3rd July. We possess a detailed account of the way 
in which this visit was brought about, through the Latin 
exercise-book of the Prince, in which he was in the habit of 
writing letters, sometimes fictitious, sometimes really ad- 
dressed to those about him.^ In the beginning of April 
1592 he was obliged to leave Copenhagen, where the plague 
had appeared, and on the way to Frederiksborg Castle he 
received from Tycho's friend Kaas so lively a description of 
Uraniborg, that he became very anxious to pay a visit to 
Hveen. He at once composed a Latin letter, probably 
addressed to his governor, in which he requested leave to 
proceed to Hveen, and as he met with a refusal, he appealed 

' Barretti Historia Ccelestis, p. 498 ; Kepler, De SteUa Martis, ( Opera omnia, 
iii. p. 211). 

2 Carteggio, p. 407. In a footnote Pavaro quotes a statement by J. D. 
Cassini, that he had seen a sextant which T. Brahe had got made for Magini 
by a workman sent from Denmark, and that-M. sold the sextant as soon as 
the workman was gone. No doubt this " workman " was G-ellius. . 

^ Published in the Danish Nyt Eistorish Tidshrifi, vol. iii. ; compare T. 
Lund, HistorisTce Skitser efter utryJcte KUder, Copenhagen, 1876, p. 322 et seq. 


to the Chancellor, from whom he at once obtained the 
desired permission, as Kaas was only too glad to see the 
future king interested in Tycho and his work. Unluckily 
the plague had made its appearance on the island, and 
Tycho, who on the 29th of April had been informed of 
the intended visit, thought it his duty the next day to send 
one of his pupils over to Seeland to announce this.-* The 
messenger found the Prince at the shore, just about to 
embark, and the youth could only console himself in his 
disappointment by composing a new exercise the next day, 
in which he expressed the hope that there might be nothing 
to hinder the visit in the coming month of June. The 
prince was evidently determined that nothing should prevent 
him from seeing Tycho's observatory as soon as possible, 
and it is much to be regretted that he did not, five years 
later, show an equally strong desire to keep the great 
astronomer in his own country, notwithstanding all the 
complaints brought against Tycho by his detractors. On 
the present occasion he got his own way. In June the 
Prince's governor was obliged to take his charge to the 
manor of Horsholm (about fourteen miles north of Copen- 
hagen, and only a mile and a half from the sea), and this 
temporary residence, which the spreading of the plague 
had rendered necessary, was most convenient for the visit 
to Hveen. When Tycho therefore arrived on the 30th of 
June to announce that the plague had vanished from 
Hveen, the Prince's governor could not find any excuse for 
preventing the future king from visiting the astronomer, 
and on the 3rd July the Prince started, attended by two of 
the protectors. Admiral Munk and Jorgen Ptosenkrands, and 
his governor, Hak Ulfstand. The weather was most favour- 
able, and the trip was no doubt thoroughly enjoyed by the 
Prince, whose excellent education enabled him to view with 

^ Cort Axelsen from Bergen ; see the Meteorol. Diary. 


intelligent interest the many strange objects whicli Tycho 
had to show him. In particular, he admired a small brass 
globe, which, by an internal mechanism, showed the motions 
of the sun and moon. Tycho immediately begged him to 
accept it, and in return the Prince took off a massive gold 
chain in which his own portrait was suspended, and hung 
it round his host's neck.-^ The conversation between the 
astronomer and his youthful guest turned to fortification, 
navigation, shipbuilding, and other branches of applied 
science, in which the Prince had been instructed, and it is 
stated that Tycho on this occasion received a promise of an 
annual grant of 400 daler (;^9i) for instructing young men 
in the theory of navigation, and astronomy, and an allow- 
ance of 120 daler annually for the keep of each pupil. ^ 
The Prince was greatly pleased with his visit, and seems to 
have regretted that it was but a short one, as he wrote 
in his Latin exercise the next day that he returned to 
Horsholm " long before supper." 

Historical events, whether trifling or important, are often 
by posterity, without any reason, connected with others 
or supposed to have caused them. Tradition afterwards 
made out that Christopher Valkendorf was in the Prince's 
suite on this occasion, and it has been related in detail how 
he and Tycho became enemies because Valkendorf kicked 
one of the dogs which King James had presented to Tycho, 
while the latter in turn abused the offender. But this 
story, which, according to other writers, refers to a later date, 
rests on a very slender foundation indeed, and at any rate 

^ Astron. inst. Mechanica, fol. B. (where for 1590 should be read 1592). 
Tycho had already in 1589 procured a couple of globes for the Prince from the 
Dutch artist Jacob Floressen (Florentius), who sent his son to Hveen to 
obtain correct star-places for his globes, which Tycho declined to give in 
writing, while he allowed him to examine the great globe in the library 
(Progym., p. 274). In 1600 Tycho sent a star-globe to the Elector of Saxony. 

^ Lund, Eistoriske Shitser, p. 353, quoting Slange's Christian den Fjerde's 
Ilistorie (1749). I have not seen this mentioned elsewhere. 


the incident cannot have occurred on this occasion, as it is 
quite certain that Valkendorf did not attend the Prince on 
his visit to Hveen. During the summer of 1592 Tycho 
had a number of other visitors, among them Prince Vilhelm 
of Courland, a brother to the Duke.^ 

But though Tycho's position still seemed an excellent 
one, and he continued in the undisturbed possession of all 
his sources of income, he seems about this time to have 
become dissatisfied and annoyed by various circumstances. 
In the letter to the Landgrave in 1591 in which he 
described the state of Denmark,^ he remarked that there 
were certain unpleasant obstacles which hindered him from 
carrying out successfully all that he had planned for the 
restoration of astronomy, but he hoped to get rid of these 
and other obstacles in some way or other, and any soil was 
a country to the brave, and the heavens were everywhere 
overhead. These last words (" omne solum forti patria est 
coelum undique supra est ") are very similar to some which 
he had used six years before in the poetical letter to Kaas, 
and they seem to indicate that already at this time he was 
not unfamiliar with the idea of seeking a home outside 
Denmark, if circumstances should make the stay at Hveen 
unpleasant to him. Among his causes of annoyance was 
a quarrel with one of the tenants on the estate of the 
Eoskilde prebend, which does not place Tycho in a very 
favourable light, and which may, perhaps, account for the 
coldness shown by the governor of the Prince when the visit 
to Hveen was proposed. It appears that Tycho and the 
tenant, Rasmus Pedersen, had had some difference in the 

' Tycho calls hira in the diary Vilihelmus, Dux Curlandiie et SemigalliEe 
{i.e., Semgallen or Samogitia, the south-east part of Courland), but he was not 
a Duke, and never became one. He probably visited Denmarlc to endeavour 
to enlist the sympathy of that country for Courland, which had a difficult 
position between Russia and Sweden. 

^ Fpist, p. 198, last line. The letter is dated Cat. Augusti, which should be 
Cal. Aprilis, as may be seen from the Landgrave's answer. 


year 1590) as the latter got the mayor of Roskilde and 
anotlier man to go oyer to Hveen on the i Sth July to try 
and settle the matter.-*- They cannot, ho-wever, have suc- 
ceeded, and Tycho -wanted a decree of eviction against the 
tenant, but the court -which tried the matter, and -which -was 
composed of four noblemen, did not grant the decree. Tycho 
no-w appealed to the king, -who summoned the four nobles 
and the litigants to appear before the High Court of Justice 
in July 1591. From the judgment of the four Commis- 
sioners it appeared that the tenant had been disobedient 
and had refused to come to Tycho -when ordered, but that 
Tycho, notwithstanding the lease for life -which the tenant 
held of his farm, had let other people plough and sow the 
land, and in the previous October (six months before he 
tried to have him legally evicted) had taken the farm from 
him. Tycho had furthermore taken the la-w into his own 
hands by having Rasmus put in irons at his own table, 
from -whence he -was carried off to Hveen, -where he was 
detained for sis -weeks or more. And as Rasmus had 
represented that he had feared the severity of Tycho, and 
did not go to him when ordered because Tycho would not 
give him a safeguard, the Commissioners had thought that 
six weeks' imprisonment was a sufficient punishment for 
this act of disobedience, and that Rasmus should not be 
evicted from the farm, of which he had only purchased the 
lease four years before, and on which he had built a house. 
Although Tycho had forbidden Rasmus to work his farm, 
this was not according to law, as long as the tenant had 
not legally forfeited his lease. As to the house on the farm, 
which Tycho complained had been sold by the tenant, it ap- 
peared that it was still standing in the garden, and formed 

^ Meteor. Diary. In Breve og Aktstyleker, p. 3, is a letter from Tycho dated 
June 1591 to the Rector of the University asking for the testimony of Dr. 
Krag and Magister Kolding, -who had been present at Hveen when the two 
men came over from Koskilde. 


part of tte farm. Purtter Tycho alleged that a certain 
house had been sold and not entered on the accounts ; but 
as Rasmus Pedersen denied all knowledge of any such mat- 
ter, and Tycho had not submitted any evidence to prove his 
assertion, the tenant had been acquitted of this charge. 
He had been obliged to go over to Hveen to work for his 
landlord with four horses and two carts, and two of the 
horses had died ; but the Commissioners had found that 
Rasmus was in no way bound to work for his landlord. 
Some boxes belonging to him had been sealed and carried 
off while he had been locked up, and these Tycho had been 
ordered to hand over unopened to the tenant. When asked 
in the Court of Appeal what objection he had to the judg- 
ment of the Commissioners, Tycho stated that he had hardly 
any objection to make, except that the case had been greatly 
delayed, and that the Commissioners had not tried the entire 
case, but had referred some parts of it to the local court,^ 
others to the provincial court,^ notwithstanding that the 
royal command had ordered them to judge in all matters 
between Tycho and his tenant ; they had also passed over 
some questions, and not tried them at all. To this the 
Commissioners answered that the delay had merely been in 
having their seals affixed to the judgment ; that they had 
been justified in referring some matters to the local court, 
as the case about a man who was drowned in a well was 
clearly a case for a jury, while other things were under the 
jurisdiction of the provincial court ; and as to the matters 
which they were said to have passed over altogether, they 
were not aware of any such matters. The High Court of 
Justice concurred with the Commissioners in every respect, 
and ordered that their judgment should stand. ^ 

^ Herredsthing, i. e. , court of the hundred. 
^ Landsthing. 

^ The whole judgment is printed in Danske Magazin, ii. pp. 274-278 
(Weistritz, ii. pp. 216-224). 


It might have been expected that the humiliation of 
having had the judgment upheld, against which he so need- 
lessly had appealed, would have been enough for Tycho, and 
that he might have left Easmus Pedersen alone in future, 
but this he evidently could not persuade himself to do, 
although we know very little about the further progress of 
the case. In February 1592 Tycho had to attend the pro- 
vincial court at Eingsted, in Seeland, as a Latin epigram 
has been preserved which he wrote on the way home, and 
in which he complains of unfair treatment by the judge.'' 
The case tried on that occasion was probably one of those 
referred to the provincial court by the Commissioners. 
From the end of the same year a draught of a royal letter 
has been found (dated 17th November 1592) which shows 
that Tycho was still persecuting the tenant. The letter 
states that whereas Easmus Pedersen has complaiaed that 
he was still kept out of his farm, and that his brother and 
his servant had been imprisoned, and were still detained by 
Tycho, whUe he was most anxious to be left in peace, since 
he had built a house on the farm, and would be utterly 
ruined if this quarrel did not cease, the kiag desired that 
Tycho should remember the misery of the man, and act in 
a Christian, reasonable, and lawful manner towards him, so 
that the Crown would not be obliged to interfere and pro- 
tect him, particularly as he was a tenant of an estate which 
was merely granted to Tycho during pleasure. It was 
therefore the royal command that this case be finally 
settled and arranged by the judge of the provincial court of 
Seeland and some other gentlemen, who were to judge in 
all matters which had not already been judicially decided. 
Tycho was therefore desired to nominate some impartial 
gentlemen who might be ordered to act on this commission.'' 

^ Also printed in Danske Magazin, ii. p. 279 (Weistritz, ii. p. 226). 
2 Banske Magazin, 3rd Series, vol. iv. p. 263. 


NotMng further is known about Kasmus Pedersen and his 
disagreeable landlord, who seems to have acted in a re- 
markably high-handed manner in the whole affair. He 
certainly did not by this conduct improve his credit 
with the young king, who throughout his life wished to 
act justly by everybody, irrespective of rank and social 

Another source of trouble to Tycho, for which he also 
had himself alone to blame, arose soon after out of his pre- 
bend at Koskilde. We have seen that the possession of 
this prebend brought with it the obligation to keep in good 
repair not only the residence attached to it, but also the 
"Chapel of the Holy Three Kings" in the Eoskilde 
Cathedral. Though perfectly willing to enjoy the income 
of the prebend, Tycho seems altogether to have neglected 
to look after the state of the chapel, and in August i 5 9 1 
the Government found it necessary to draw the attention of 
the Chapter to the want of repair of the chapel. Having 
been informed that Tycho was bound to see to this, a letter 
was written on the 30th of August to Tycho in the king's 
name about this matter. Tycho does not appear to have 
taken any notice of this reminder, and the king had to 
write to him again in August 1 5 9 3 > that he had himself 
been in the cathedral, and found the roof, the woodwork, 
and the vault in so dilapidated a state, that it was to be 
feared that it would all come down unless something was 
done before the winter. Tycho was therefore desired to 
repair the chapel at once, and if he did not do so, the king 
would have it done by a builder at Tycho's expense. But 
Tycho did nothing, and in consequence received in Sep- 
tember 1594a third reminder, in which he was informed 
that if the chapel was not repaired at latest before Christ- 
mas, the prebend would be conferred on somebody else. 
Now at last Tycho thought he had better do something. 


and applied for leave to take down the arcted roof of the 
chapel and put a flat ceiling in its place, which would sim- 
plify the repairs, and this he received permission to do in 
November i S94 ; but he did not carry out his proposal, and 
he must have managed to repair the chapel in some other 

Tycho's conduct in these various transactions could not 
but undermine his position in Denmark, and there was 
doubtless more than one of his feUow-nobles who took the 
opportunity of fanning the flame of discontent with the 
self-willed and highly-paid astronomer which gradually 
sprang up among the rulers in Denmark. Among these, 
Tycho had hitherto had a very powerful friend in the 
Chancellor, Niels Kaas, but he died in June 1594, and 
after his death Tycho must have felt himself less secure in 
the enjoyment of his several endowments. Possibly Tycho 
may also gradually have become tired of the continued 
residence on the lonely little island, from which his very 
frequent trips to Scania and to Copenhagen ^ cannot always 
have been pleasant, particularly in winter, and he may by 
degrees have become desirous of making a change. He 
had not been outside Denmark since 1575, and must have 
longed for the easy intercourse with learned men which he 
had once hoped to find at Basle, and for which the occa- 
sional visits of learned foreigners to Hveen was not a 
sufficient compensation. Reports must also have reached 
him of the great love of astronomy and alchemy of the 
Emperor Rudolph II., and the thought may easily have 
arisen in his mind that he might find the same liberality 
in the German monarch as he had formerly found in King 
Frederick. With the Emperor's physician, Hagecius, Tycho 

1 Danshe Magazin, ii. 281-283 ; Werlauff, De hellige tre Kongcrs Kapd i 
Roeshilde Domkirke, Copenhagen, 1849, p. 18 et seq. 
^ See the Diary, passim. 


had continued to correspond, and he had even a more in- 
fluential ally in the Imperial Vice-Chancellor, Jacob Curtz 
of Senftenau, with whom he had also exchanged letters, 
and who in 1590 had sent him the privilege for his 
writings which Hagecius -had some years before promised 
to get for him, together with a description of a method of 
subdividing arcs designed by Clavius, which is based on 
the same principle as that afterwards, in a more practical 
form, proposed by Vernier.^ According to Gassendi, Curtz 
went to Denmark not long before his death (which took 
place in 1594), on the pretence of coming on the Emperor's 
busiaess, and offered Tycho to intercede with the Emperor 
to procure an invitation to Bohemia in case he should wish 
to leave Denmark ; he is even said to have offered Tycho 
his own house at Prague, and to have left a plan of it with 
Tycho in case he might wish to have any alterations made 
in it.^ After Curtz's death, Hagecius is said to have 
assured Tycho that the new Vice-Chancellor, Rudolph 
Corraduc, would not fail to befriend him. 

It was perhaps with a view to the probability that he 
might soon wish to leave Denmark that Tycho disposed of 
his portion of the famUy property of Knudstrup, which, 
since the death of his father, he had possessed jointly with 
his brother Steen, and which his sons, as born of a " bond- 
woman," could not have inherited. The date of this sale is 
not known, but it must have been previous to the loth 
August I 594, on which day he signed a document by which 
he reserved to himself the right to continue to call himself 
" of Knudstrup," without any injury to the rights of his 
brother or his brother's heirs.^ 

' Astr. inst. Meehanica, fol. G-. 6 ; Delambre, Astr. moderne, i. p. 253. 

^ Gassendi, p. 131. I have not succeeded in finding Gassendi's authority 
for this. Curtius is not mentioned in the Meteorological Diary, so he can 
hardly have been at Hveen. 

^ Danske Magazin, 4th Series, ii. p. 325. It is characteristic of the careless 


Among the causes which finally induced Tycho to leave 
Denmark, the quarrel with his former pupil, Gellius Sasce- 
rides, is supposed to have been an important one. We have 
mentioned that Gellius spent about two years in Italy. On 
the return journey he was at Basle for some time (159 2—9 3 ), 
where he became a Doctor of Medicine, and he reached 
Denmark some time in i S 9 3 • He soon after began to 
visit Uraniborg, and eventually became engaged to Tycho's 
eldest daughter, Magdalene, at that time about nineteen 
years of age. Gellius would hardly have thought of aspu-- 
ing to the hand of any other nobleman's daughter, but the 
peculiar position of Tycho's chUdren, by many people not 
considered to be legitimate, may have given him courage. 
Tycho does not appear to have objected to the proposed 
marriage, and may have thought that the undoubted learning 
of GeUius made up for any supposed deficiency in lineage.^ 
But the pleasant relations between Tycho and Gellius did 
not last long, probably because the latter during his long 
absence abroad had become unaccustomed to the imperious 
manner of Tycho, and the quarrel commenced in earnest in 
the following year, when the wedding began to be talked 
about. It appears that Tycho did not care to have festi- 
vities and expense in connexion with the ceremony, and 
further demanded that Gellius, after the wedding, should 
remain at Hveen for a while to assist in the work ; and not 
content with this, he made certain stipulations as to the 
manner in which Gellius was to provide his wife with 
clothes, &c. On the other hand, Gellius is said to have 

manner of spelling names which prevailed in those days, that Tycho Brahe's 
name in the document is spelt Tygge Brahe, in the signature Thyghe Brahe. 
In Latin or German he always wrote Tycho, in Danish generally Tyge. 

1 The following account is taken from Dr. Rordam's paper in the Danske 
Magazin, 4th Series, ii. p. 16 et seq., which is founded on documents in the 
archives in the Copenhagen University which were not accessible to Laugebek 
(Z». J/., ii. p. 285 ciscj.). 


expected a dowry with his bride, while Tycho refused this, 
adding that if he would not take the girl for her own sake, 
he should not have her at all. In the autumn of I 594 the 
end of all this disagreement was that Gellius broke off the 
match. Still he seems about that time to have been fre- 
quently at Hveen, and Tycho wrote to his sister that all 
might yet be well if Gellius did not become vacillating 
again. But during an interview between Gellius and Tycho 
they quarrelled again about the matter, in consequence of 
which Tycho sent two friends, to Gellius to demand a clear 
answer to the question whether he would accept the pro- 
posed terms or not. At first Gellius would not give a deci- 
sive answer, but during the next few days (in December 
I 594) he told one of the intercessors. Professor Krag, more 
than once, that he did not want Tycho's daughter ; and on 
learning this, Tycho and his daughter sent Gellius a formal 
notice that the engagement was at an end.'- In a letter to 
a friend (which was afterwards produced), Magdalene Brahe 
expressed herself thankful that all was over. 

Gellius was greatly blamed by many people, but he tried 
to shift the blame on others, particularly on Krag, saying 
that he himself was joking or drunk when he spoke to the 
latter, and that his words were not intended to be carried 
further. Tycho, therefore, in the beginning of January 
1595, got Krag to give him a written account of all that 
had happened between him and Gellius, as he particularly 
wished his sister Sophia to have an unbiassed explanation. 

' Krag was perhaps hardly a safe person to employ in a delicate mission. 
He had recently been appointed royal historiographer, and had the following 
year the meanness to accept all the materials laboriously gathered by Tycho's 
friend Vedel, whom the Government forced to deliver up all his collections, 
because he had delayed the writing of his Danish history so long. Krag told 
Tycho in a pointed manner that he was glad that it had only fallen to his lot 
to describe the youth of Hveen and not its decay, by which he meant that his 
history was to stop at the death of King Frederick II. Wegener's Vedd, 
p. 200. 



At the same time ( 1 1 th January) Tycho wrote to the Eector 
of the University, and requested a statement from him and 
the professors to prevent GelKus from throwing all the blame 
on him and his daughter. This led to an agreement being 
drawn up five days later between the parties, which was 
signed and sealed by the rector and four professors,^ and 
Tycho now seemed content. But the aifair had of course 
been talked about, and Gellius continued his attempts to 
place himself in the best possible light. Tycho in the end 
got tired of this, and in February i 596 he again requested 
the University to investigate the whole aflfair, and let all 
documents laid before the academic senate by himself or 
his adversary be registered by the notary.^ About the 
same time he drew up a Hst of all the accusations of Gel- 
lius,^ and invited him to prove them before the professors. 
Gellius made several attempts to prevent further proceed- 
ings, but failed to do so, and formal conferences before the 
academic senate were commenced on the 25 th February. 
They were continued off and on till the month of July, 
when everybody was probably so thoroughly sick of the 
wearisome twaddle, which could not lead to anything, that 
the matter was allowed to drop. The details of the pro- 
ceedings * give scarcely any information about the origin of 
the quarrel, but it can hardly be doubted that Gellius would 
not have dared to trifle with Tycho and his daughter if he 
had not seen how unpopular his former master had become ; 

1 Alluded to in Danshe Magazin, ii. p. 292 (Weistritz, ii. p. 250), as a 
" contract ; " it does not seem to be in existence now, 

2 On the 5th February 1596, Tycho had procured a royal order to the 
Chapter of Lund to judge the matter, as Gellius had obtained a medical 
appointment in Scania, and therefore in matrimonial matters was under the 
jurisdiction of the said Chapter ; but it is not known what action the Chapter 

' Printed in Danshe Magazin, ii. p. 286 (Weistritz, ii. p. 239). The charges 
of GeUius relate to the demands that he should stay at Hveen, keep his wile 
in fine clothes, &c. 

■• Danske Magazin, ii. pp. 291-307 (Weistritz, ii. pp. 248-281). 


and on the other hand, it is probable that Tycho's domineer- 
ing manner first brought about the difference between him 
and Gellius which led to this unpleasant affair.-' 

During the years when all these annoyances happened 
to the astronomer, his scientific work continued to be carried 
on, and the years 1594 and 159S are considerably richer 
in observations than those immediately preceding. Most 
of his observations for determining accurate places of fixed 
stars were made before the end of 1592, and the results 
were embodied in a catalogue of TJJ stars for the end of 
the year 1600, which is printed in his Progymnasmata. 
After 1590 it was especially the planets which were 
observed (though they had always been regularly attended 
to), and in 1593 extensive series of observations of Mars, 
Jupiter, and Saturn were made. In 1595 observations of 
fixed stars were resumed in order to bring the number of 
stars in the catalogue up to looo, and even in the first 
two months of 1597, immediately before leaving Hveen, 
some observations were taken in hot haste to make up the 
thousand (^pro com/plendo millenario), mostly only depending 
on a single measure of the declination and the distance 
from one or two known stars, and sometimes with a rough 
diagram to identify the star. It must therefore be taken 
cum grano salis when Tycho already in January 1595 
wrote to Rothmann that he had now finished " about a 
thousand stars," and when he writes in his Mechani'ca that 
the great globe was quite finished in 1595, exhibiting a 
thousand stars.^ It has been suggested that it was this 

1 Gellius married in 1599, became Professor of Medicine in the Copen- 
hagen University in 1603, and died 1612 (Rordam, I. c, p. 31). Magdalene 
Brahe went with her father to Prague, and apparently never married. 

^ Longomontanus says in bis Astronomia Banica, p. 201, that the work on 
the star-catalogue was commenced in 1590, and went on for five years ("Ego 
. . . huic de fixis ccelitus restituendis negocio et exsecutioni non solum inter- 
fui, sed etiam praefui"). 


completion of Tycho's star-catalogue wMch he wished to 
commemorate by the striking of a medal (or rather two, 
slightly different) bearing the year 1595. This is quite 
possible, and he may have wished, in the midst of all his 
worry and vexation, to have a memorial of the work carried 
on for nearly twenty years at Hveen.'' A more lasting 
memorial of his activity and of the respect with which he was 
treated by any one able to value his work was the collec- 
tion of letters exchanged between him, the late Landgrave 
of Hesse, and Rothmann. Rantzov had long ago suggested 
the publication of this series of scientific essays, and copies 
of some of them had been sent to Hagecius and Peucer, 
who had expressed a similar wish. They were printed in 
Tycho's own office, and form a quarto volume of 310 pp., 
and 38 pp. of laudatory poems, dedication, and preface.^ 
The title shows that l^ycho intended afterwards to publish 
letters to and from other astronomers, an intention which 
he did not live to carry out, so that only some of these 
letters have of late years been published. None of Tycho's 

^ One of these medals (in silver) is in the royal numismatic collection in 
Copenhagen, described and figured in Vanske Magazin, ii. p. 161, and Weis- 
tritz, ii. p. 14. It is about ij inch in diameter, and shows on one side Tycho 
Brahe's portrait, and round it " Effigies Tychonis Brahe 0. F. set. 49 " 
(O. F. means Ottonis Filii), on the other his coat of arms, and round this his 
motto : "Esse potius quam haberi. 1595." The other medal is in a collec- 
tion at Prague (Friis, T. Brahe, p. 363), and is a quarter inch more in dia- 
meter ; the only other difference is the inscription round the arms : " Arma 
genus fundi pereunt, durabile virtus," (and inside this) "Et ductrina decvs 
nobilitatis habent." 

^ " Tychonis Brahe Dani, Epistolarum astronomicarum Libri. Quorum pri- 
mus hie illustriss. et laudatiss. Principis Gulielmi Hassiee Landtgrauij ao ipsius 
Mathematici Literas, vnaque Responsa ad singulas complectitur. Vraniburgi. 
Cum Cffisaris Sc Regum quorundam priuilegiis. Anno MDXCVI." Colophon 
is the vignette with " Svspiciendo despicio," and underneath : " Vranibvrgi Ex 
officinS. Typographies Authoris. Anno Domini MDXCVI." The portrait of 
Tycho which appears facing the title-page is from 1586, and is engraved by 
Geyn of Amsterdam. There is a copy of it in Gassendi's book. The printing 
must have commenced before 1590, as Gellius had given Magini a few 
printed leaves of the book (Carteggio, p. 233). 


otter letters can, however, compare in importance witli the 
lengthy essays exchanged between Hveen and Cassel, which 
give a most instructive picture o£ the revolution in practical 
astronomy effected by Tycho. The dedication to Landgrave 
Maurice alludes to the origin of Tycho's acquaintance with 
Landgrave Wilhelm, the renewal of it through Rantzov in 
1585, praises the Landgrave for not having studied astro- 
nomy in books but in the heavens, and quotes from a 
funeral oration in which the hope had been expressed that 
the correspondence of the deceased with Tycho Brahe might 
be published, as it would show the world the merits of the 
Landgrave's scientific work. In the preface Tycho refers 
to the length of time necessary to form a complete series of 
observations by which the restoration of astronomy might 
be accomplished. Though the solar orbit may be suffi- 
ciently investigated in four years, the intricate lunar course 
requires the study of many years, while it takes twelve 
years to follow the oppositions of Mars and Jupiter round 
the zodiac, and even thirty years to see Saturn move round 
the heavens. He had commenced his own observations at 
the age of sixteen, though the results of the first ten years' 
work were less accurate than the later ones. Ptolemy and 
Copernicus had not observed for such a length of time, and 
consequently the numerical values of astronomical constants 
had not been well determined by them. As already re- 
marked, most of the letters are in Latin, only those of the 
Landgrave and some of Tycho's replies to him being in 
German, with a liberal sprinkling of Latin words and 
sentences, which almost render unnecessary the Latin 
translation which always follows.i As also mentioned 

^ Here is a specimen from the Landgrave's first letter (to Rantzov) : 
" Darneben woUen wir euch auch nicht verhalten, das vff angebeu Paul 
Vvitickij, wir vnsere Instrumenta Mathematica dermassen verbessert, dass, da 
wir zuuor kaum 2 Min. scliarff, wir jetzo i ja J einer min. obseruiren kiinnen. 
Haben vns derhalben vff die Art Quadrantem Horizontalem desgleichen ein 


above,'' there is towards tlie end of the volume a description 
of the instruments and buildings at Hveen, with woodcuts of 
the latter. Of the instruments, seven were already figured 
in Tycho's other books, and it appears that to a few copies 
of the Efiistolce he added an appendix of eleven leaves, with 
figm'es of some of the instruments, and on the last leaf a 
short note promising that a complete account of all of them 
should soon appear. This appendix was doubtless only 
printed in a very few copies, as it was soon to be rendered 
superfluous by the publication of Tycho's special book on 
his instruments.^ 

While the printing of Tycho's correspondence was being 
completed important events took place in Denmark. Tycho's 
last remaining influential friend, Jorgen Rosenkrands, died 
in April 1596, and the young king, who was now in his 
twentieth year, was soon afterwards declared of age, and was 
crowned on the 29th August at Copenhagen.' He had 
appointed Christian Friis of Borreby, Chancellor, and 
Christopher Valkendorf to the oflSce of High Treasurer, 
which had been vacant since the death of Tycho's con- 
nexion, Peder Oxe, in i 5 7 5 ; but King Christian had both 
the wUl and the ability to govern himself, and soon made 
his authority felt and respected. He was personally of an 

Sextantem, ad ohseruandas distantias Sidlarum inter se, lassen zurichten, jedes 
von gutem Messing vnd bicubitaZ. Halteu auch drei Gesellen, Astronomice <(■ 
Ob$eruatiomim peritos ad iustificanda loca Stellarum Fixarum." Letters from 
learned men, if not written altogether in Latin, were generally written in tliis 
mongrel tongue. 

^ See above, p. 211. 

2 This appendix or pamphlet ("loones instrumentorum qvorvndam Astro- 
nomiie instaurandse gratia a Tychone Brahe Dane diligentia, impendioqve 
inestimabili elaboratorvm") is mentioned by Friis, Tyge Bralie, pp. 363-364. 
In 18S9 I tried in vain to get a look at it at the Royal Library at Copen- 
hagen, but it was not there. These pictures are alluded to in Tycho's letter 
to the Chancellor of the 31st December 1596. 

^ Tyoho attended the coronation (Meteor. Diary), .ind a few days after he 
was visited by Johann Muller, " Mathematious administratoris Brandenbur- 
genais." See also Gassendi, p. 153. 


economical disposition, and at once began to introduce 
reductions in various branches of the administration. 
Among others who were made to feel the change of govern- 
ment was Tycho Brahe, who lost the Norwegian fief "im- 
mediately after the coronation," as he tells us himself/ As 
this was a serious loss to Tycho, he made an effort to re- 
cover the fief, or at least to be allowed to keep it till the 1st 
May, the usual time for giving up possession of beneficiary 
grants. On the 31st December 1596 he therefore wrote 
a lengthy letter in Latin to the new Chancellor, Friis,^ 
pointing out how deeply interested King Frederick had been 
in his work, and how death alone had prevented him from 
carrying out his intention of permanently endowing the 
observatory at Hveen; how much he had done for the 
advancement of astronomy, as might be seen from the 
correspondence just published, and of which he would have 
sent King Christian a copy if the king had not been 
absent in Jutland. For the present, he only asked to have 
the Norwegian estate restored, or at least to let him keep 
it till May, as his steward would then have paid him the 
rents. With this letter Tycho sent a copy of his Epistolce 
and a copy of the declaration of the Privy CouncU of 1589, 
promisiug to advise the king to endow Tycho's observatory 
in a permanent manner. In reply, the Chancellor, who was 
with the king in Jutland, on the 20th January I 597 wrote 
in a short, business-like manner, that he had laid Tycho's 
petition before the kiag, but that his Majesty did not see 
his way to pay anything from the Treasury towards the 
maintenance of the instruments, and that it was impos- 
sible to postpone the surrender of the Norwegian fief, 
as the maia fief of Bergen (to which that of Nordfjord 
belonged) could not spare the income from it. But if the 

^ In his Latin account of how he left Denmark. Barrettus. Hist. Cod., p. 8oi 
^ Tycho had first applied to Valkendorf, but in vain [l. c). 


Chancellor could oblige him in any other way, he should 
be happy.'' 

It is very difficult to form an idea of the motives which 
dictated this changed behaviour of the king and the Govern- 
ment to the great astronomer, but there can hardly be any 
doubt that Tycho had made himself more than one enemy 
among the nobles, and these found in his own conduct 
faults enough which they could point out to the king, 
hinting that this self-willed man, who would hardly con- 
descend to obey the royal authority, had been petted long 
enough, and that there was no necessity for continuing to 
spend great sums of money on his instruments, the more so 
as it could not be a secret that he was by no means devoid 
of pecuniary resources himself. When they had reminded 
the king of Tycho's persecution of the tenant near Eoes- 
kilde, of his having not only neglected to attend to his 
duty of keeping the chapel of his prebend in repair, but 
also turned a deaf ear to repeated injunctions about this 
matter, it was probably not difficult for his enemies to in- 
fluence the young king. Who these enemies were is not 
known with absolute certainty. Tradition mentions among 
them the king's physician, Peder Sorensen, with whom 
Tycho had, about twenty years before, exchanged friendly 
letters, but who is said to have become jealous of Tycho's 
dabbling in medicine, and particularly of his having dis- 
tributed remedies against various diseases without payment. 
But Tycho himself considered Christopher Valkendorf and 
Christian Friis as having been the principal instigators in 
the events which led to his expatriation ; at least he did so 
some time afterwards, when he mentioned them as such in 
several letters.^ As early as about fifty years after these 

' The two letters are printed in Hofman's Portraits historiques des hommes 
iUustrcs de Danemarc {1746), vi. pp. 14-16, and in Danske Magazin, ii. pp. 
310-314 (Weistritz, ii. pp. 289-297). 

' In a letter to Professor Grynasus at Basle, dated 8th October 1597, Tycho 


eveuts it was currently believed tkat tte ill-feeling between 
Valkendorf and Tycho arose from a quarrel about a dog, 
but the story is told in different ways. We have already 
alluded to the version of the story according to which the 
quarrel occurred on the occasion of the visit of the young 
king. to Hveen, and it was pointed out that Valkendorf was 
not at Hveen at that time. The well-known French writer, 
Pierre Daniel Huet, who was at Copenhagen in 1652, tells 
the story differently.^ According to him, an English envoy 
had a dog which Tycho wanted for a watch-dog at Urani- 
borg; but as Valkendorf also coveted it, and the envoy 
wished to keep friendly with both of them, he promised to 
send them each a dog when he went home. But when the 
dogs came, one was much finer and larger than the other, 
and the king, who was asked to arbitrate between them, 
gave the large one to Valkendorf, which roused Tycho's ire 
and caused the enmity between them. But all this probably 

says that " duo Dynastffi," either from ignorance of science, or from hatred 
and malice towards him, or from both causes, got his endowments taken from 
him. In a letter to Magini, dated 3rd January 1600, Tycho speaks in stronger 
terms. He wanted Magini to get some Italian writer to compose a panegyric 
on him, and had sent Magini some materials for this, but he mentions that he 
does not want his country, nor the king, nor the nobility at large to be abused, 
as most of these had nothing to do with his exile. " Perstringendi vero solum- 
modo pro merito Cancellarius modernus et Aulse Magister ; qui cum patrise 
honorem ex officio promovere debuissent, eum potius ob avaritiam et sorditiem 
pari invidia, malignitate et odio coniunctum (cum ipsi liberalibus scieintis vel 
nihil vel admodum parum tincti essent) impediverunt et externiinarunt. 
Nomina eorum inveuies in iis quae de oaussis discessus mei Latine exarata 
nunc mitto." He adds that their names are as well worth preserving as that 
of Herostratos who burned the temple of Diana at Ephesus I (F. Burckhardt, 
Aus Tycho Brakes Briefwechsel, Basel, 18S7, pp. 10 and 14. Magini printed 
the letter in his Tabulm primi Mohilis, but left out the above passage, which, 
therefore, does not occur in the Carteggio, p. 418.) 

' Danslcc Magazin, ii. p. 322, quotes Th. Bartholin, Be mediema Danorum 
(1666). Gassendi (p. 140) also knows the story. 

^ Pet. Ban. Huetii, Fpiscopi Abrincensis, Commentarius de rebus ad eum 
pertinentibus. Amstelodami, 1718, I2mo, p. go. Huet was on his way to 
Queen Christina of Sweden when he visited Copenhagen and Hveen. As he 
mentions the Danish savant Ole Worm, he may have had the story from 


rests on no other foundation than rumour only ; and though 
Valkendorf as Treasurer may have been instrumental in 
depriving Tycho of some of his income, he can hardly have 
been his declared enemy, and a letter which Tycho wrote 
to him in May 1598 does not look as if there was any 
hostility or even coldness between them. But it is a 
necessity for human nature to have a scapegoat, and, with 
a rare unanimity, astronomical historians have told their 
readers that Valkendorf was the sole cause of Tycho's exile, 
and several of them indulge in very pretty expressions of 
indignation against that monster.^ Of course they are not 
aware that Valkendorf's name is in very good repute in 
Denmark, where he distinguished himself not only as a 
statesman, but also as a promoter of learning by founding 
a college for poor students in connexion with the University.^ 
It is far more likely that Friis, the new Chancellor, was an 
active enemy of Tycho's, and we shall see that he reaped a 
pecuniary advantage from the disgrace of Tycho. ^ As to 
the young king, there is every excuse fof him, for it is 
really not strange that he should have thought it desirable 
to diminish the annual burden to the Treasury, which was 
without precedent, and which undoubtedly might be reduced 
without seriously interfering with Tycho's scientific work. 

The Norwegian estate was not the only endowment 
which Tycho lost before leaving Hveen. On the i8th 
March IS97, Valkendorf received the king's order that 
Tycho's annual pension of 500 daler from the Treasury 

^ For instance : " Son nom doit Stre cit^ pour ^tre reserve k I'infamie et 
devout a I'ex^cration des eavans de tous les %es." Lalande's Astr., i. p. 196 
(2nd edit.). 

* "Valkendorf's Collegium" (founded 1589) is still in existence. Valken- 
dorf died in January 1601. 

' If Friis was really so great an enemy of Tycho's, it is very curious that 
he should a few years after act as Maecenas to Longomontanus, Tycho's 
favourite pupil. See the preface to his Astrcmomia Uanica. 


should cease. ^ If Tyclio had not ah-eady commenced his 
preparations for leaving Hveen, he did so at once after 
this last blow. Though certainly not a poor man (for he 
was able sis months later to invest io,000 daler, or about 
;^2200, a very considerable sum at that time), he would 
have been unable in future to maintain a large staif of 
observers, printers, and other assistants ; the extensive 
buildings would require some outlay to keep them in repair, 
and the idea of retrenching could not be pleasant to him.'' 

These considerations, added to the natm-al feeling of dis- 
gust at the want of appreciation he had met with, and 
the wish again to enjoy the society of congenial minds, 
overcame the regret he must have felt at leaving the happy 
home where he had lived for fuUy twenty years, the build- 
ings he had raised, and which had been the wonder of the 
age, and the hitherto obscure little island on which he had 
conferred imperishable fame. The observations, which had- 
been progressing as usual, were discontiuued on the i 5 th 
March (on which day the last ones, of the sun, moon, and 
Jupiter, were recorded), and the dismantliug of the iastru- 
ments, and the removal of these and other property to his 
house at Copenhagen, were rapidly proceeded with. Under 
the 2 1st March we read iu the Meteorological Diary : " We 
catalogued all the Squire's books ; " and we can picture to 
ourselves the desolation which soon reigned in the hitherto 
crowded library and observatories. 

But Tycho was not allowed to leave Hveen without 
further annoyance. When the peasants on the island found 
that their master was not in favour at court, they di-ew up 

' See Tyoho's account, "De occasione interruptarum observationum et 
discessus mei," Barretti, Hist. Cod., p. 8oi. The date is given in Friis, Tune 
Brake, p. 229. 

- In addition to Hveen, he still held the prebend of Roskilde and the eleven 
farms in Scania ; the rent from the latter was barely 200 daler a year (Weis- 
tritz, i. p. 170). 


a memorial complaining of his oppression and ill-treatment 
of them. On the 4th April the king, therefore, commanded 
the Chancellor and Axel Brahe (apparently a brother of 
Tycho's, who in June 1596 had become a privy councillor) 
to proceed to Hveen on Saturday the 9th April, in order to 
examine on the following day into the complaints of the 
tenants, to inspect the land, and also to see "if he has 
dared to act against the ritual, as you. Christen Friis, are 
aware." The report of this expedition is not known, but 
proceedings were at once taken against the clergyman at 
Hveen for having acted contrary to the Church ritual. 
On the 14th April the following commission was issued to 
a privy councillor, Ditlev Hoik : " Know you, that whereas 
a minister, by name Jens Jensen, has dared during the 
service in church to act against the ritual, and he for such 
audacious conduct is to appear before our beloved the 
honourable and learned Dr. Peder Winstrup, superinten- 
dent ^ of this diocese of Seeland, on the 2 2nd April : We 
order and command that you arrange to be present here in 
this town at the same time, and afterwards with the said 
Peder Winstrup in the said case to judge according to what 
is Christian and right." ^ The judgment of these two 
commissioners is not known, but in an old diocesan record 
it is stated that " the minister of Hveen was dismissed in 
disgrace for not having kept to the ritual and prayer-book in 
the form of baptism ("I adjure thee "), but acting differently; 
also for not having punished and admonished Tyge Brahe 
of Hveen, who for eighteen years had not been to the 
Sacrament, but lived in an evil manner with a concubine." ^ 
In other words, the clergyman had omitted the exorcism 

' After the Reformation the Danish Bishops were for some time styled 
STiperintendents, but the old name soon came into use again. 
^ Banske Magazin, ii. p. 316 (Weistritz, ii. p. 300). 
2 Ibid., p. 317. 


in tlie baptismal service, a great crime in a Lutheran 
country, because it had been omitted by Zwingli and 
Calvin, but retained by Luther.^ The " concubine " would 
a few years earlier have been called Tycho's lawful wife, as 
we have already shown, and though Tycho may not have 
been a regular attendant at the church of Hveen, he was 
unquestionably a man of a religious mind, as many pas- 
sages in his writings show very clearly.^ Bishop Winstrup 
was not very friendly to Tycho (as had appeared during 
the proceedings about Gellius before the University), and 
the minister of Hveen was probably not a very desirable 
person, as he afterwards, while staying with Tycho in Hol- 
stein, tried to make mischief between him and the steward 
left behind at Hveen.^ That Tycho should not generally 
have conformed to the usage of the Lutheran Church seems 
unlikely when we remember his intimate friendship with 
Vedel, as well as the fact that there were several future 
clergymen, and not less than four future bishops, among his 
resident pupils. 

^ It is curious that King Christian IV. already in 1606 desired Bishop 
Winstrup, when a little princess was being christened, to leave out the 
exorcism. D. Mag., ii. 319. 

^ Ricoioli quotes Progymn., pp. 712, 777, to show that Tycho had too much 
veneration for Luther, Melanohthon, and Chytrseus, " those pests of the human 
race " (Kiistner, Gesch. der Math., ii. p. 407). Gassendi, on the other hand, 
by several extracts shovi's how full of true religious feeling Tycho always was 
when speaking of the Creator of the Universe (p. 190 et seq.), 

3 DansJce Mag., ii. p. 318 (Weistritz, ii. p. 305), quoting a letter from Tycho 
to Holger Kosenkrands. In the above-mentioned letter to Grynseus, Tycho 
thus describes the incidents narrated above : " Accesserunt et alite non pau- 
culse tribulationes, quibus abitum meum eo citius promoverunt, adeo ut ne 
quidem a Parocho meo in mei contumeliam et despeotum persequendo ab- 
stinuerint, quod is detestandum et impium istum Exorcismum in Psedobaptismo 
meo conscio omiserit. Ideoque officio privatum, et per integrum mensem 
citra latam sententiam inoarceratum, parum abfuit, quin etiam capite plecte- 
rent, nisi ego cum meis Amicis apud reliquum Regni senatum tantam seevitiam 
avertissem. Quin et Rusticos tarn contra me quam eundem Parochum meum 
clanculavie exoitatos tantum aberat, ut secundum leges (prout urgebam) eorum 
iniustam perfidiam et rebellionem refrsenare voluerint, nt potius horum im- 
merita defensione suscepta in malitia illos confirmarint. Ego autem Parochum 
tandem ex istis afHictiimibus liberatum in Germaniam mecum reoepi." 


It is not quite certain whetlier Tyclio was still at Hveen 
during the montli of April, while his treatment of the 
tenants and the conduct of the clergyman were being in- 
vestigated. By the end of March the removal of his instru- 
ments, printing-press, and furniture had been completed, 
and only four of the largest instruments were left behind 
for a while, as too troublesome to move.'' Shortly after 
Easter, Tycho Brahe and his family left their home at 
Hveen for ever, and took up their residence temporarily at 

^ These were : Armillse maxima3 (with the equatorial arc belonging thereto), 
and Quadrans chalybeus magnus, both at Stjerneborg ; the great Mural 
quadrant and SemioirouUis magnus azimuthalis, the latter of which was in the 
southern observatory at XJraniborg. See Tycho's account, De occasione inter- 
rupt, obs., Barrettus, p. 8oi. 

^ The diary and the account in the observing ledger (Barrettus, p. 8oi) 
differ as to the date of Tycho's departure from Hveen. In the latter he says 
that he left the island with his family " statira a Pasohatis Festo die 29 
Aprilis" (most distinctly written in the original MS.). But Easter was the 
27th March. The diary is silent from the 22nd March to the loth April in- 
clusive, " propter alias occupationes observasse aut notasse non potuimus," 
and under April 1 1 it has : ** Primum ingressi sumus novum Musseum Haf- 
niense." On the 1 7th April : " Prof ectus est Tycho Roschyldiam." The diary 
stops abruptly on April 22nd at the middle of a page, and was never taken 
up again. Probably it was on the 29th March that Tycho left Hveen, and 
this is confirmed by his German account, in which he says that he was at 
Copenhagen "in die dritte Monat," i.e., more than two months. 


ARRIVAL AT PRAGUE {1597-1599). 

Whex Tyclio arrived at Copenhagen in April 1597, te pro- 
bably did not intend to make a long stay there, but merely 
to watch events for a short time. He can hardly have 
intended to settle in his house at Copenhagen and continue 
his work there, as he had the Isle of Hveen for life, and 
might as well have stayed there if he had any wish to 
remain in Denmark, unless, indeed, the troubles at Hveen 
had risen to such a height that the island had become 
odious to him. He had brought his instruments, chemical 
apparatus, and priating-press with him, but he does not 
appear to have commenced astronomical observations at the 
tower on the rampart close to his house. Probably he had 
not time to get any of the larger instruments mounted, as 
he tells us in the account of his leaving Denmark, as well 
as in several of his letters, that the Treasurer, acting in the 
name of the king, who was absent in Germany, forbade him 
to take observations in the tower on the rampart. He does 
not say on what pretext this was done, but possibly the 
Government did not wish him to settle permanently on anv 
part of the fortification.^ He is also said to have been for- 

' In the account "De interruptione," &c. (Barrettus, p. 8oi), as well as in 
a letter to Tedel in 1599 (Weistritz, i. p. 171), Tycho says that the order not 
to observe on the rampart was given by Aulre Magister [i.e., Valkendorf), 
though he had been one of the four protectors who had granted him the use 
of the tower in 1589. See also a letter to Vincenzio Pinelli of Padua {Axis 
T. Brake's Briefwechsd, p. 12). 



bidden by the mayor, Carsten Kytter, to make chemical 
experiments in bis own bouse, and Gassendi adds tbat be 
and bis clergyman were subjected to personal annoyance, 
and tbat be was not able to obtain legal reparation ; but 
tbis doubtless refers to tbe troubles at Hveen, and not to 
anything wbicb happened at Copenhagen.''- But an event 
which at first sight looks even more strange took place 
soon after. On the 2nd June, Thomas Fincke, Professor of 
Mathematics (afterwards of Medicine), and Iver Stub, Pro- 
fessor of Hebrew, were ordered to proceed to Hveen, as the 
king bad learned that the peasants had damaged tbe instru- 
ments ; they were to examine into this matter and report 
on it.^ Their report is not known, and tbis expedition is 
not mentioned in any of Tycho's accounts of bis expatria- 
tion, except in his poem Elegia ad Daniam (which will be 
mentioned farther on), and a garbled account of it may 
have reached him after his departure from Denmark. Ac- 
cording to Gassendi, tbe two professors declared that the 
instruments were not only useless, but even noxious curio- 
sities,' which probably only referred to the chemical appara- 
tus. Fincke had in 1583, at Basle, published a Geometria 
Ilotundi,in the preface to which be bad addressed some highly 

^ Tycho says (Barrettus, p. 802) : " Taoeo nunc, quse circa reprobos istos 
Insulares et Parochum in odium mei evenerunt " (compare footnote 3 on page 
237). In a letter to Pasclialius Mulaeus (Claus Mule, one of his pupils), of 
unknown date, but found among the MSS. of Longomontanus, Tycho says 
(after describing how he had lost his endowments and had been forbidden by 
the mayor to carry on his exercitia) : " I shall also pass over what happened 
to my clergyman from hatred to me, also the insolence shown to me by those 
who were instigated to it, also that I was forbidden to take legal proceedings 
against them" (Bang's Samlinger, ii. p. 493 ; Weistritz, i. p. 1 55). Cissendi, 
p. 140, uses almost the same words, and has Ihem probably from the same 

- Fi-iis, T. Brake, p. 234, quoting from the original document in the archives 
at Copenhagen. 

' Gassendi (p. 140) evidently knows very little beyond the allusion to the 
trip in the Elegy J he only knows the name of one of the emissaries, and mis- 
spells it Feuchius. He does not mention that any damage had been done to 
the instruments. 


complimentary sentences to Tycto, and the book is the 
earliest in whicli the words secant and tangent are proposed, 
while several new fundamental formulae of trigonometry 
occur in it for the first time, so that the author must have 
been a man of considerable ability.^ The mission of the 
two professors was no doubt caused by some disturbances 
at Hveen, which, perhaps, had more to do with Tycho's 
departure than we are aware of, and it is much to be 
regretted that we do not possess any account of these 
transactions except Tycho's own. Gassendi thinks that the 
report of the professors was the cause of Tycho's chemical 
experiments being forbidden ; but this cannot have been the 
case, as the expedition of the two learned professors must 
have taken place after the 2nd June, and Tycho must have 
left Copenhagen either on that date or immediately after it, 
as he arrived at Rostock during the first half of June. 

After having spent two or three months at Copenhagen, 
Tycho must have felt that there was nothing to be obtained 
by delaying his departure from Denmark any longer, and 
early in June iS97 he sailed for Eostock with his family, 
some students and attendants, about twenty persons in all, 
taking his instruments, printing-press, &c., with him. His 
principal assistant of late years, Longomontanus, who 
wished to study at German universities, had obtained his 
discharge with a kind testimonial from Tycho, dated at 
Copenhagen on the ist June.^ Among those who accom- 

^ See particularly pp. 77-78, and p. 292, rule 15. About this book, compare 
R. Wolf, Handbuch der Astronomie, pp. 173, 179) ^^^ Catalogue of Crawford 
Astr. Library, p. 188. Kastner (i. p. 629) does not seem to have perceived the 
valuable parts of the book. Tinoke (1561-1656) was first physician to the 
Duke of Holstein-Gottorp, then Professor of Mathematics, and from 1603 of 
Medicine at the University of Copenhagen. He had studied at Strassburg 
and Padua, and correspondecl for some years with Magini. According to 
Lalande and Poggendorff, he wrote previous to 1603 several tracts on astro- 
nomical subjects, but after 1603 he devoted himself only to medicine. 

^ This testimonial is printed by Gassendi, pp. 140-141. Tycho calls himself 
" Dominus hsereditarius de Knudstrup et arcis Uraniburgi in insula Danise 
Venusia Fundator et Prseses." 



panied Tycho was a young Westphalian gentleman, Franz 
Gansneb Tengnagel von Camp, wlio had been with him at 
Hveen since 1595) ^^^ '^I'O afterwards became his son- 

At Rostock Tycho had still friends from former days, 
though his correspondent BrucEeus had died four years 
previously. But Chytrseus was still alive, and on the i6th 
June he wrote a friendly letter, regretting that the state of 
his health prevented him from paying his respects to Tycho.^ 
But the exiled astronomer found that though he was at 
once welcomed to Germany, he had not improved his posi- 
tion in Denmark, for immediately after his departure, on 
the loth June, he was deprived of the prebend of Eoskilde, 
which was conferred on the Chancellor, Friis, although the 
latter already enjoyed the best prebend in the chapter, and 
though the rules were that nobody could hold more than 
one prebend in any cathedral, that they were tenable for life- 
time, and that the heirs of a prebendary should enjoy annum 
gratim after his death. ^ But here it must in fairness to 
the Government be recollected that Tycho had for years 
showed the most complete disregard of his obligations as 
a Prebendary, and that he had apparently left the country 
for ever in order to obtain employment abroad wherever 
he could get it. There was, therefore, some excuse for 
depriving him of this lucrative sinecure ; but it certainly, 
on the other hand, seems to point to Friis as an enemy of 
Tycho's, since he made this an occasion for feathering his 
own nest. 

When Tycho Brahe had been about a month at Rostock, 
he took a step which he probably ought to have taken long 

' Letter in Sanshe Magazin, ii. p. 325 (Weistritz, ii. p. 318). 

^ Ibid., p. 325. ThatFriia already had another prebend is stated by Tycho 
himself, ibid., p. 348 (Weistritz, ii. p. 346). Tycho says [Hist. Coel., p. 802, 
that he was * ' vix e patria egressu3 " when this happened. He must, there- 
fore, have left Copenhagen between the 1st and loth June. 


before, and addressed himself directly to King Christian IV. 
As it is of great interest, we stall give a translation of the 
letter, keeping as closely as possible to the words of the 
Danish original."^ 

' ' Most pnissant, noble King, my most gracious Lord ! 
with my willing and bounden duty most humbly declared. 
I beg most humbly to inform your Majesty, that whereas I 
had no opportunity of appearing before your Majesty before 
my departure, neither knew whether it might be agreeable 
to your Majesty or not, I am now obliged shortly to let 
your Majesty know in writing what I should otherwise 
humbly have stated verbally. 

" Whereas from my youth I have had a great inclination 
thoroughly to study and understand the laudable astrono- 
mical art, and to put it on a proper foundation, and for 
that purpose formerly hoped to remain in Germany in order 
conveniently to do so, then your Majesty's father of laud- 
able memory, when H. M. learned this, graciously desired 
and induced me to undertake and carry out the same at 
Hveen. Which I have done for more than twenty-one 
years with the greatest diligence, and at great expense, 
believing to have thereby shown that I liked best to do 
it to the honour of my own Lord and King and of my 
country. And your Majesty's father graciously intended 
and promised that whatever I started in the said art should 
by a foundation be sufficiently endowed and perpetuated on 
several good conditions which were graciously promised me, 
which your Majesty's Lady mother, my most gracious 
Queen, doubtless still remembers, and formerly has stated 
to the Privy Council of Denmark. For that I have received 
the public act of the Privy Council on parchment, confirm- 
ing and further assuring me of this. Therefore I have 

1 The original is printed in BansJce Magazin, ii. pp. 327-330, translated in 
Weistritz, i. p. 122 et seq. 


since incurred great trouble and expense, even more than 
formerly, hoping that your Majesty when coming to the 
Government would be graciously pleased to let me and mine 
profit thereby. But it has turned out differently from what 
I had believed, about which I shall now only state the 
following. Tour Majesty is doubtless aware that I have 
been deprived of what I should have had for the main- 
tenance of the said art, and that I have been notified that 
your Majesty does not intend further to support it, in 
addition to much else which has happened me (as I think) 
without my fault or error. And whereas I, by the grace 
of God, shall have to carry to an end what I once with so 
much earnest and for so long have worked at, which is 
also known to many foreign nations and greatly desired, 
and I have not myself means for this, as I have been so 
reduced that I, notwithstanding the fiefs I held, have been 
obliged to part with my hereditary estate ; therefore I 
trust that your Majesty will look to my necessities, and not 
be displeased with this my departure, as I for these and 
other reasons am greatly in need of seeking other ways and 
means, that what has been well begun may be properly 
finished, and that I may maintain my good name and repu- 
tation in foreign countries. Bat I have not departed with 
the intention of totally leaving my native land, but only to 
look for help and assistance from other princes and poten- 
tates, if possible, so that I may not too much be a burden 
to your Majesty and the kingdom. If I should have a 
chance of continuing my work in Denmark, I would not 
refuse to do so, for I should still as formerly much prefer 
to do as much as I can to the honour and praise of your 
Majesty and my own native land in preference to any other 
potentates, if it could be done on fair conditions, and with- 
out injury to myself. And if not, though it be ordained 
that I am to remain abroad, I shall always be subject to 


your Majesty with all respect and humility and humble 
capacity. Submitting also to the gracious consideration of 
your Majesty, that it is by no means from any fickleness 
that I now leave my native land and relations and friends, 
particularly at my age, being more than fifty years old and 
burdened with a not inconsiderable household, which I, at 
great inconvenience, am obliged to take abroad. And that 
which is still left at Hveen proves that it was not formerly 
my purpose and intention to depart from thence. Hoping, 
therefore, humbly, that when your Majesty considers these 
circumstances, your Majesty will be and continue my 
gracious Lord and King, and with all royal favour and 
gra-ce incline toward me and mine. I shall always be 
found humbly true and dutiful to your Majesty to the best 
of my ability, wherever the Almighty sends me. The same 
good God who rules all worldly government grant your 
Majesty during your reign happiness, blessing, good counsel 
and design. Datum Rostock the loth July 1597." 

The same day Brahe wrote a letter (in Latin) to a young 
friend, Holger Eosenkrands (afterwards known as a writer 
on religious subjects), in which he thanked Eosenkrands 
for a letter he had just received, which showed that 
Ovid's words, " quam procul ex oculis, tam procul ibit 
amor," could not be applied to him. He had desired a 
painter to send a portrait of himself to Eosenkrands. He 
would like to know what was going on in Denmark, and 
what people said about his departure. He was stUl staying 
at Eostock, waiting for the return of the Danish embassy,^ 
in order to speak to his brother Steen, and he had been 
advised by some people versed ia state affairs not to apply 
to any foreign Government before he was assured as to the 

'■ Probably this was an embassy to Coin an der Spree (Berlin) in connection 
with the approaching marriage of the king with Anna Cathariua of Branden 


intentions of the Danish king ; hut if he found that his 
Majesty was unfavourable to him and his studies, he ex- 
pected confidently to find advice elsewhere. 

It would almost seem that Tycho already regretted having 
left Denmark, as he now made every effort to influence 
King Christian in his favour, though he had neglected to 
approach the king personally while he was still in the 
country. On the 29th July he wrote a letter in German 
to Duke Ulrich of Mecklenburg-Giistrow, the maternal grand- 
father of the king, reminding him of the visit which the 
Duke had once paid to Uraniborg, and stating that he 
had been obliged to leave Denmark for reasons which he 
did not wish to put in writing. For the present he had 
taken up his abode at Rostock, which he hoped was not 
displeasing to the Duke, who doubtless would regret that 
work, which was progressing well and which was valued by 
learned men all over Europe, should be so suddenly in- 
terrupted and almost come to nought. He therefore begged 
the Duke to advise him how this work might be continued, 
if not in Denmark, then somewhere in the Roman Empire, 
and promised in future publications gratefully to acknow- 
ledge any assistance the Duke would give him. At the 
same time Tycho wrote to the Duke's chancellor, Jacob 
Bording, whose father had been physician to King Chris- 
tian III. of Denmark, and asked the chancellor to speak for 
him to the Duke. Bording answered at once, assuring Tycho 
of the good-wiU of the Duke, who would in a few days 
write to him as well as to the king. On the 4th August 
Duke Ulrich wrote to Tycho, expressing his sympathy, and 
asking whether Tycho would wish him to send off a letter 
to King Christian, of which he enclosed a copy. He could 
not express an opinion as to how the astronomical work 
might be carried on, but it would require the patronage of 

^ DansJce Magazin, ii. 330 (Weistritz, ii. p. 322). 


some great potentate. In Hs letter to the king the Duke 
merely asked his grandson not to allow Tycho's work to be 
interrupted, as it did great credit to the late king and the 
country, and was renowned among all nations. 

While Tycho Brahe was still at Eostock awaiting the 
result of his own and the Duke's letters to the king, he 
occupied himself in investing the ready money which he 
had brought with him from Denmark. As he repeatedly 
states that he had been obliged to part with his hereditary 
estate on account of the great outlay on buildings and 
instruments, which all his endowments did not coyer, it 
would almost seem certain that his aunt and foster-mother, 
Inger Oxe, who died in 1591, must havp left him a very 
considerable sum of money.^ He found a very convenient 
way of investing his money, as the Dukes Ulrich and Sigis- 
mund August, as guardians of the young Dukes Adolph 
Friedrich I. and Johann Albrecht II. of Mecklenburg, hap- 
pened to require money, and were willing to borrow from 
Tycho. In the summer of 1597 they opened negotiations 
with him for the loan of 10,000 " harte Eeichsthaler " {i.e. 
of full value, not clipped). As a prudent man, Tycho 
wanted proper security, and demanded a bond, by which 
ten well-known men should declare themselves and their 
heirs bound to him in the sum of 10,000 thaler; but as it 
was not customary in Mecklenburg for sureties to bind their 
heirs, he had to give up that point. As it took time to 
procure the consent and the signatures of the sureties, Brahe 
agreed to pay the money on receiving a temporary receipt 
from the two ducal guardians, and a mortgage on the county 
of Doberan ; but when this was settled and two oflBcials came 

' These letters are printed in the Danske Magazin, ii. pp. 330-336 
(Weistritz, ii. p. 323 et seq.). 

^ Several letters between Tycho and his kinsman Eske Bille (from the 
years 1599-1600) seem to show that Tycho had some dispute with several 
other heirs of his aunt. See Breve og Aktstyhlcer, pp. 49 and 99. 


for the money, he would not pay it, as the receipt did not 
contain a certified copy of the bond to be given by the ten 
men, and did not specify the interest to be paid. At last 
everything was settled and the bond was delivered, dated 
the 24th August 1597, to " Tycho Brahe auf Knustorf 
im Eeiche Danemark erbgesessen," after which the money 
was paid.^ 

In the meantime the plague had appeared at Eostock, 
but Tycho still liagered there, awaiting the reply to his 
letter to the king. If, before he took the decisive step 
of removing his family, his great treasure of observations, 
and nearly all his instruments out of the Danish dominions, 
Tycho had addressed himself to the king, who was of an 
open, generous nature, it is not unlikely that he might 
have been treated very difierently ; but to an impartial 
observer it is not strange that the king should be offended 
with a subject whose previous behaviour had been far from 
faultless, who had left the country in a huff in order to 
carry his talents to the most profitable market, and who 
now declared himself willing to forget the past and come 
back if it was made worth his while. Of the interference 
of his grandfather the king took no notice whatever,^ but 
to Tycho's own letter he sent on the 8th October the fol- 
lowing answer, which we also translate literally.^ 

" Christian the Fourth, by the grace of God of Denmark 
and Norway, the Vends and the Goths, King, &c. Our 
favour as hitherto. Know you that your letter which you 
have addressed to us sub dato Eostock the i Oth day of July 
last, has been humbly delivered to us this week, in which 

' G. C. F. Lisch, Tycho Brahe und seine VerJialtnisse zu Meilenburg, pp. 
9-to {Jahriilcher des Vereins fiVr TneTdenburgwche Ge$chickte, xxxiv.). 

' See Tycho's letter to Vedel of September 1599 (Weistritz, i. p. 172). 

' The Danish original in Danske Magazin, ii. p. 336 et seq., translated by 
Weistritz, i p. 1 26 e( gcj. 


among other things are counted np, first, that you had no 
opportunity to speak to us before you left this kingdom, 
neither knew whether it were convenient to us or not ; 
therefore you have humbly wished to let us know j'our case 
in writing, and [you add] that we are doubtless aware that 
you have lost whatever allowance you hitherto have had for 
the maintenance of the astronomical art, also tha,t we will 
not continue to support the said art, and other things which 
unexpectedly have occurred and have happened to you with- 
out any fault or error of yours, as you think. Furthermore, 
that you have not yourself the means to perfect the said 
art at your own expense, and even though you had your 
former benefices, you have yet been so reduced as to have 
had to part with your estate. And whereas you for the 
said reasons are obliged to seek in other places from foreign 
potentates and lords help, assistance, and counsel to promote 
the astronomical art, then you beg that we will not with 
displeasure look upon your journey, particularly as you will 
not altogether leave your native land. Furthermore, you 
state that if it may be granted to you in this kingdom to 
continue your work, then you would not refuse it, but grant 
that honour to us and your native land, if it could be done 
on fair conditions and without injury to you, as your 
lengthy letter furthermore details it. Now we would 
graciously not withbold from you, first, as regards that you 
have not had an opportunity of speaking to us before 
you left the kingdom, and that you were not aware whether 
it would be agreeable to us or not: You must well re- 
member that you were staying for some weeks in our city 
of Copenhagen before you left the kingdom, and not only 
did not ask authority from us to leave the country, as yoa 
should have done, but never even spoke to us except on the 
one occasion when the peasants of Hveen and you were in 
court before us, and you were commanded and ordered to 


appear before us at the castle. And althougli you do 
not blush to make your excuse for this in a manner as 
if you were our equal, we desire in this letter to let you 
know that we are aware of that, and that we expect from 
this day to be respected by you in a different manner, if 
you are to find in us a gracious lord and king. As regards 
your not doubting that we are aware that you have lost 
some fiefs you had held, and your thinking that it happened 
through no fault or error of yours ; you remember well 
what complaints our poor subjects and peasants at Hveen 
have had against you, how you have acted about the church 
there, of which you for some years took the income and 
tithes and did not appoint any churchwarden, but let it 
stand ruinous ; also took the land from the parsonage ; and 
partly pulled down the houses, and the parson who should 
live there and use the land to keep himself and his wife, 
him you have given some pennies per week and fed him 
with your labourers, so that there have been during some 
years many parsons, who yet did not receive a call from the 
congregation in accordance with the ordinance, nor were 
lawfully dispossessed. In what way the words of baptism 
for a length of time have been omitted, against the estab- 
lished usage of these kingdoms, with your cognisance, is 
too well known to everybody. Which things, as well as 
others, which have occurred on that poor and small land, 
and were known to us for a good while before it became 
publicly known, have caused us to grant our tenants and 
the crown's in fief to others who would keep them under 
the law, right, and established custom."'' With regard to 
your not being wealthy enough to promote the astronomical 
art by your own means, but sold your hereditary estate 

1 This refers to the fief of Nordfjord and the estate of the Eoskilde prebend. 
The Island of Hveen could not be taken from him as he had got it for life, 
and we shall see that Tycho continued to keep a steward there, and received 
rent and produce from the island. 


■while you yet lield your fiefs, so that you have left the 
kingdom to ask for help from foreign potentates, and not 
intending to leave your native land altogether, which 
journey you humbly ask us not to take umbrage at : there 
is great doubt whether you have spent the moneys you 
received for the property you sold on astronomical instru- 
ments, as it is said here that you have them to lend in 
thousands of daler to lords and princes, for the good of 
your children and not for the honour of the kingdom or 
the promotion of science. Also it is very displeasing to us 
to learn that you seek for help from other princes, as if we 
or the kingdom were so poor that we could not afford it 
unless you went out with woman and children to beg from 
others. But whereas it is now done, we have to leave 
it so and not to trouble ourselves whether you leave the 
country or stay in it. Lastly, as you humbly state that if it 
might be permitted you to finish your work in this kingdom 
you would not refuse if it could be done without injury to 
you ; now we shall graciously answer you that if you will 
serve as a mathematicus and do what he ought to do, then 
you should first humbly offer your service and ask about it 
as a servant ought to do, and not state your opinion in such 
equivocal words (that you will not refuse it). When that 
is done, we shall afterwards know how to declare our will. 
And whereas your letter is somewhat peculiarly styled, and 
not without great audacity and want of sense, as if we were 
to account to you why and for what reason we made any 
change about the crown estates ; and we besides remember 
how you have published in your epistles various nonsense 
about our dear father, to the injury both of his love and 
of yourself ; now we by this our letter forbid you to issue 
in print the letter you wrote to us, if you will not be 
charged and punished by us as is proper. Commending 


you to God. Written at our Castle of Copenhagen the Stli 
October Anno 1597. Under our seal, 


(Address) — " To our beloved, the honourable and noble 
Tyge Brabe of Knudstrup, our man and servant." 

The barsh and angry tone of this letter shows how com- 
pletely the king's mind had become estranged from Tycho ; 
and no matter how badly Tycho may have treated his in- 
feriors, the fact remains that he was in his turn treated 
with severity and a want of appreciation of his great scien- 
tific merit which is inexcusable. It could not be expected 
that the king or his advisers should have been able to ap- 
preciate the true value of Tycho's scientific labours, but they 
could not help being aware that he enjoyed a world-wide 
reputation, such as no Dane had ever acquired before ; and 
if he was a bad landlord, they might have endowed him 
in some other way. But this is neither the first nor the 
last time that a Government has given science the cold 
shoulder, since even in later and much more enlightened 
times statesmen of all nations not unfrequently have dis- 
tinguished themselves by a sovereign contempt of science. 
But all the more let us admire the truly enlightened mind 
of Tycho's great benefactor and friend. King Frederick 
the Second, whom he had unfortunately lost too early. 
King Christian seems to have felt personally offended with 
Tycho Brahe for having first retreated to a distance and 
then attempted to make terms with him. But it is not 
impossible that Tycho may have thought of Vedel, who 
in 1595 had not only been deprived of his office of his- 
toriographer for delaying too long to write the Danish 
history, but had even been forced to deliver up all the 
materials which he had been collecting for years. Possibly 
Tycho wished to bring his great treasure of observations out 


of the reacli of envious people, wlio might suggest that it 
had been gathered at the public expense, and therefore was 
public property ; but by doing so he destroyed the bridge 
behind him, and could now only look abroad for a place to 
continue his labours. 

As Tycho had no reason to remain any longer at Ros- 
tock, where the plague besides made the stay unpleasant if 
not dangerous, he now accepted the invitation of Heinrich 
Rantzov to reside for a while in one of his castles. Of 
these, Wandsbeck, which had been rebuilt not long before, 
seemed to Tycho the most convenient, as it was situated 
close to Hamburg (only two or three miles north-east of it), 
and the intercourse with foreign countries, therefore, was 
easy. As Rantzov, who was a very wealthy man, had spent 
great sums on accumulating books and treasures of art in 
his various castles in Holstein and Slesvig, Tycho found at 
Wandsbeck (or Wandesburg, as the new castle was called) 
not only a comfortable dwelling, but also one in which the 
owner's refined tastes had created a home which might to 
some extent bear comparison with the one he had left 
for ever. Tycho removed with his family and belongings 
to Wandsbeck about the middle of October IS 97, and met 
a former acquaintance there in the person of Georg Lud- 
wig Froben (Frobenius) from Wiirzburg, who six or seven 
years before had visited Uraniborg after studying at 
Tubingen and Wittenberg. He was at that time probably 
employed by Rantzov at Wandsbeck in literary work, and 
he settled in the year 1600 as a printer at Hamburg, where 
he remained till his death in 1645.^ 

Tycho could now think of resuming the observations 

which had been interrupted seven months before. On the 

20th October he wrote a short statement of the causes of 

this interruption and of his departure, which we have 

'_ Jooher's Gelchrten Lexicon, vol.. ii. 


already quoted/ and a long poem " Ad Daniam Elegia," 

in which lie taxes his native land vrith having rewarded 

him with ingratitude. It begins thus : ^ — 

" Dania, quid merui, quo te, mea Patria, Isesi 
Usque adeo ut rebus sis minus sequa meis ? 

Scilicet illud erat, tibi quo nocuisse reprendar, 
Quo majus per me nomen in orbe geras ? 

Die age, quis pro te tot tantaque fecerat ante, 
Ut veheret famam cuncta per astra tuam ? " 

The writer next inquires who is to make use of the 
precious things which he has left behind. " Somebody 
has been sent to Hveen who was believed to know Urania's 
secrets ; he came, and when he beheld the great sights 
(though but a few are left), he stared with wonder. What 
could an ignorant man do, who had never seen such things ? 
He inquires their name and use, but lest he should seem to 
have been sent thither in vain, he sneers at what he does 
not comprehend, probably instructed by my enemy, who 
already before has injured me." The poem further alludes 
to all he has done for science, and how little his Herculean 
labours have been valued ; how he has cared the sick with- 
out payment, and suggests that this perhaps has roused 
the envy of his enemies. He regrets that his ungrateful 
country shall lose the honour which he conferred on it, but 
he looks to the future without fear, as the whole world will 
be his country and he will be appreciated everywhere. He 
exonerates the king from all blame, but there are a few 
others whom he never injured, but who yet have done him 
all the harm they could. Finally, he thanks Rantzov for 
having so hospitably received him. 

The statement about the interruption of the observations 

^ " De oocasione interruptarum observatiunum et discessus mei." Eistoria 
Coslestis, pp. 801-802. 

- Ibid., p. 802, also in Resenii Inscript. Hafnienses (1668), p. 347, and in 
Casseburg, Tychonis Brahe rclatio de statu suo, <tc. Jena, 1730, less correctly 
given by Gassendi, p. 143. 


and the elegy were copied into the volume in which the 
observations of the years 1596 and 1597 were written, 
and copies of the poem were sent to various correspondents. 
Though it was probably not intended for the eye of King 
Christian, it fell into his hands by accident. On a copy of 
the poem which Tycho in the following year sent to Joseph 
Scaliger he added a note to the following effect : — Rantzov 
got a copy of the poem as soon as it was written, and had it 
stitched in a calendar of his,^ and when the king in the course 
of the winter paid a visit to Rantzov at one of his other castles 
in Holstein, he happened to find the book lying open on the 
library table. The king took it up, and when he saw the 
poem with Tycho's signature underneath, he read the whole 
of it thoughtfully and slowly, though he on other occasions 
would not have been affected by such things.^ Having 
read it, he silently put down the book and never spoke to 
Rantzov about it, nor did he in conversation allude to Tycho 
Brahe. When Rantzov was told that the king had seen 
the poem, he was much vexed, but Tycho on hearing it 
only hoped that the king had understood all the allusions, 
and expressed himself ready to send the king a copy.^ 

Though Tycho Brahe had been unsuccessful in his appli- 
cation to the king and in his attempt to use the influence 
of Duke Ulrich of Mecklenburg, he still tried to bring all 
the influence he could to bear on him. In December i 597 
he went on a visit to Rantzov at Bramstedt in Holstein, 
where he met Margrave Joachim Frederic, who shortly 
afterwards became Elector of Brandenburg, and his consort, 
who were on their way home after attending the wedding 

^ Sanzovianum, CaUndarium, printed at Hamburg in 1590, described by 
Kastner, ii. p. 413. 

^ " Qui alias talibus rebus ron afficitur." 

' " Quod et adhuo facere paratus sum." This copy of the poem (2^ pp. 
folio) is now in the University Library at Lejden. See also Danske Uagazin, 
i. 340 (Weistritz, ii. p. 334). 


of their daughter and Kinor Christian at Haderslev in Slesvig, 
on the 27th Xovember. On the 22nd December Tycho 
handed the ilargrare a letter in which he expressed his 
regret to find that the king was displeased with him for 
leaving Denmark, though any one might know that he would 
not without cause have left his home with wife and children, 
and at the age of fifty. But as it perhaps had been so 
ordained by &od, he was content, and had no wish to be 
reinstated, and even if that should be done, he would be 
very unwilling to live any longer at Hveen, and always to 
stay there.^ But he would ask the Margrave to write to 
the king that he would, though abroad, continue to do all he 
could for the honour of his country, and it might perhaps 
elsewhere be done as well, if not better, and much more 
conveniently and quietly than in Denmark. If the kiug 
would carry out his father's intention, and would per- 
manently endow TJraniborg, Tycho would see that the work 
should be carried on well, if not by himself, at least by one 
of his [family], and he would let the four great instruments 
remain there, and supply others as well. In that case he 
hoped the king would endow the observatory with canonries 
in accordance with the promise of the Government during 
the interregnum. But if the king did not desire to keep 
up the observatory, he hoped he might remove the four 
iustruments, and that he might receive some compensation 
for all the trouble and expense he had gone to." 

With this letter has been preserved another memorandum 
of Tycho's reasons for going abroad, which he doubtless 

1 '* Dan ich damm keinen Verlangen trage, nunmehr vor mein Person in 
Dennemarck zn Bein nnd gerestitniret za werden, nnd wan das Bchon geehehen 
solte, so ist es mir doch Behr ungelegen auf der Insel Haen lenger zu wohnen, 
und stets zn bleiben, woven ich an einem anderen Orfc meine TJrsachen ver- 
zeichnet habe." I believe there is not any document extant in which these 
reasons for not living at Hveen are stated. 

^ Danske ilagazin, ii. pp. 342-344 (Weistritz. ii. p. 336 et sei.]. 


grave tlie iMarirrave with tlie letter.'^ In tliis memorandmn 
it is stated that Tyoho had, at the wish of TTing Frederick, 
settled at Hveen, where he had erected a number of costly 
buildings and constructed more than fifty fish-ponds, which 
were a great boon to the island, as often there was formerlr 
a scarcity of fresh water. All this, as well as his instru- 
ments, had cost over 75,000 daler, though the king and 
Council had only paid 10,500 daler towards it." "When 
the Privy Council, shortly after the king's death, had pledged 
itself to recommend the yotmg king, when he attained his 
majority, to perpetuate the observatory, Tycho had ia the 
following eight years even expended more than before. 
But after the coronation he lost first his Xorwegian fief, 
which had brought him in about lOOO daler annually, and 
soon after that he also lost his pension of 500 daler. His 
removal to Copenhagen is then mentioned, and how he was 
during the king's absence forbidden to continue his work 
there. Then, when he left for Germany, the Chancellor 
got his prebend, which was worth about 700 daler and ten 
Danish Icester corn,^ l\ing Frederick had under his hand 
and seal promised him the first vacant prebend in the Cathe- 
dral of Lund, but this had been ignored afterwards. He 
had met with these and other troubles, which he did not 
wish to put in writing, and he could only conclude that 
there was no good-will in Denmark towards him or his 
science, though he was willing to excuse the king, and to 
believe that all arose from the envy and hatred of his enemies. 
He would therefore leave all to G-od, and pray for His help 
and blessing to continue his work. 

' Diinflr .V.7 wciii. iL pp. 344-349. " Die Trs,ichen wammb Tycho Brahe sk-h 
aus Pennemaick in Teutsch'audt begeben, kurtzlich zu vermeldea, sein diese," 

^ He must mean exclusive of his :uiuu&l iucume from the various endow- 

' Abont 300 hectolitres. In ready money Tycho. therefore, had .:400 daler 
(ir53 ;i a, including the rent from the eleven farms at Sullen. See .ibove, 
p. 23,, footnote. 



On the 2 5 til January 1598, tlie Elector of Brandenburg 
(who had just succeeded to this dignity on the death of his 
father) wrote to King Christian enclosing Tycho's letter, 
which he asked his son-in-law to consider favourably. He 
also wrote to his daughter, and asked her to put in a good 
word for Tycho. These letters were sent under cover to 
Friis and Yalkendorf, with a short note asking them to do 
whatever they could in this matter. On the 4th February 
the Electress wrote to the king asking him to give a gra- 
cious answer to Tycho Brahe's petition, and to her daughter 
the queen she wrote in nearly the same terms, asking her 
to use her influence with the king to that effect.^ What 
answers were sent to these letters is not known, but at any 
rate they did not lead to anythiag. 

In the meantime Tycho had resumed the observations at 
Wandsbeck, the first being made on the 2 1st October 1597. 
During the first few months he only employed a radius, as 
in the early days of his youth, before he had got a number 
of good instruments together, and he was even obliged to 
observe the important opposition of Mars in this manner, 
as he had not yet got the heavieo; instruments transported 
to Wandsbeck and erected in suitable places. By the 
beginning of February 1598 this was done, ^ and he was 
again able to use quadrants for determining the time by 
altitude observations, instead of (as during the previous 
months) by watching when the pole-star and another star 
were in the same vertical. He also laid aside the radius 
for the more accurate sextant, and set up an equatorial 
armilla for observing the sun. On the 2Sth February 1 598 
a solar eclipse took place, which was total in the middle of 
Germany, while in Holstein about nine-twelfths of the solar 
diameter was eclipsed. Tycho observed this eclipse, and 

1 Danske Maga:in, ii. pp. 349-351 CWeistritz, ii. pp. 348 et seq.). 
- Barretti Hist. Ccel., p. 822. 


received observations from his former pupils, LongomontaiLUS, 
who at that time was staying at Eostock, and Christen Hansen 
of Eibe, who observed it in Jutland, and who had formerly 
observed the comet of 1593 at Zerbst. It appears that 
Tycho got some kind of information abont this eclipse from 
somebody at Hveen, perhaps from David Petri (Pedersen), 
whom he had left in charge of the buildings and other 
property on the island, as Tycho afterwards wrote both to 
Magini and Kepler that the eclipse had been observed at 
Hveen from beginning to end (while only the beginning 
was seen at Wandsbeck owiug to clouds), and that the time 
of beginning and end agreed well with his own tables.-^ 
With the exception of this eclipse of the sun and two of the 
moon, and a few meridian altitudes of the sun, the planets 
only were observed at Wandsbeck. Tycho felt that the 
thousand star-places were enough to have to show to the 
world, and he felt that observations of the planets were of 
greater value to complete the material accumulated at Hveen. 
He was assisted at Wandsbeck by Johanjies Muller, mathe- 
matician to the Elector of Brandenburg, who had visited 
him at Hveen in 1596, and whom he was requested by the 
Electress to train not only in chemistry but also in the 

^ In the letter to Magini (28th N'ovember 159S, Carteggio, p. 222, also p. 
23S), Tycho says that the middle of the eclipse at TJraniborg was observed at 
Ilh. 5m. A.3r., magn. of eclipse between 9 and 10 digits. In the letter to 
Kepler he wrote (Deo. 9, 1599, Opera, i. 225) that the observer at Hveen found 
by the large armillse the beginning, end, and middle, in accordance with 
Tycho's tables. In his Optics Kepler made use of this observation, and 
gave the contacts as having occurred at 10.3 and 12.32 {Opera, ii. 367), but in 
the Tab. Rudolph., p. no, he says that Origanus had observed 10^ and 12.32, 
and that the figures given in the Optics must have been copied from Origanus, 
putting 10.3 for loj (compare Opera, ii. 441). But if so, this is no fault of 
Tycho's, as be did not give any observed contacts. There is nothing about 
this observation in the Historia Calesiis, nor could I find it in the original 
volume for 1596-97. Tycho does not mention the name of the observer at 
Hveen, only in the letter to Kepler he says the observation waa made " a 
quodam istic relicto studioso." 


preparation of medicines.'^ The distinguished astronomer 
David Fabricius of Ostfriesland also visited Tycho at Wands- 
beck, but probably only for a short time. 

In addition to the observations, Tycho devoted his time 
at Wandsbeck to the preparation of the illustrated descrip- 
tion of his instruments, which he had for years intended 
to publish, and which it seemed particularly desirable to 
issue now, in order to sustain his reputation and impress 
learned and influential men with the magnitude of his 
scientific work and its great superiority over that of previous 
observers. AVoodcuts of a number of the instruments had 
already been prepared at Uraniborg, and some of them had 
been inserted in his books on the new star and the comet 
of I 577- Some engravings were now made of other instru- 
ments not yet figured, and the test was soon put together 
by enlarging the account formerly prepared for the Land- 
grave. As Tycho had brought his printing-press with him, 
he was able to have the book printed under his own eyes 
at Wandsbeck by Philip von Ohr, a printer from Hamburg. 
Early in 1598 the jistronomia; instauratce Mechanica was 
ready, a handsome thin folio volume, slightly larger than 
the reprint of 1602, and now extremely scarce, so that the 
number of copies printed can hardly have been considerable. 

1 Letter from the Electress to Tycho of 14th February 1598. Dansie 
Magazin, ii. p. 352 (Weistritz, ii. p. 353). 

^ Tychonis Bralie Astronomice Instauratce Mechanica, in the centre the 
vignette " Suspioiendo despicio," underneath, " Wandesburgi, Anno cia 10 110. 
Cum Caesaris et Regum quorundam Privilegiis." Colophon : Vignette 
Despiciendo suspicio, and under that: "Impressum Wandesburgi | in Aroe 
Ranzoviana prope Hamburguin sita, | propria Authoris typographia | opera 
Philippi de Ohr Chalcographi | Hamburgensis [ Ineunte Anno mdiio." ,Tliis 
original edition now only exists in a few great libraries. In the Royal Library 
of Copenhagen are two copies with all the pictures beautifully illuminated and 
gilt, the one presented to Grand Dulje Ferdinand de Medici, the other to the 
Bohemian nobleman " Peter Vole Ursinus, Dominus a Rosenberg ; " in the 
Strahofer Stiftsbibliothek at Prague is one presented to Baron Hasenburg 
{Astr. Nachr., iii. p. 256) ; in the British Museum is a copy presented to 


The book was dedicated to the Emperor Rudolph II., 
whom Tyoho was now specially anxious to interest in Lis 
labours. The dedication, which is dated the 3 i st December 
1597, refers- shortly to the instruments of the ancients and 
the limited accuracy attainable with them, and gives a 
summary of the contents of the book. Then follow (after 
a poem by Holger Rosenkrands) figures and descriptions of 
the seventeen principal instruments used at Uraniborg and 
Stjerneborg; of the sextant used in 1572—73 (two figures), 
of the great quadrant at Augsburg, and of a mounting once 
used for the largest azimuthal quadrant, and superseded by 
the one figured as No. 7. We shall not here dwell on 
these descriptions of Tycho's instruments, as they will be 
considered in some detail in the last chapter, and some of 
them have already been alluded to in previous chapters. It 
was natural that Tycho should at that time, with an un- 
certain future before him, point with some satisfaction to 
the convenient construction even of the larger instruments, 
which enabled him to take them asunder for the sake of 
transportation to different parts of the world. For an astro- 
nomer must be cosmopolitan (" Oportebit enim Astronomum 
esse Koar/uLOTToXiTiji' "), as among statesmen there are rarely 
found any who admire his studies, but frequently those 
who despise them. But the student of this divine art should 
not care about the opinions of ignorant people, but only 
think of his studies, and if interfered with by politicians or 
others, let him move himself and his belongings to some 

Hageoius, &c. On the front cover of these presentation copies is Tyoho'a 
portrait stamped in gold, with the inscription round it : 

" Hie patet exterior Tychonis forma Brahei,] 
Pulchrius eniteat, qvis latet interior." 

The bacli: shows his coat of arms (a golden pale on azure ground), with the 
distich round it : 

" Arma, genus, fundi pereunt, Durabile virtus 
Et doctrina decus nobilitatis liabent."" 


other place^- preferring kis beavenly and sublime endeavours 
even to his native soil, and remembering tliat — 

"Undique terra infra, ccelum patet undique supra 
Et patria est forti quselibet ora viro." ^ 

After the illustrated description of instruments follows a 
short account of six smaller portable instruments and an 
engraving and description of the great globe. Tycho next 
gives a sketch of his life from his youth onwards, his travels, 
and how he became settled at Hveen, and passes in review 
the principal results of his observations ; ^ the improved 
elements of the solar orbit ; the discovery of a new in- 
equality in the moon's motion ; the variability of the inclina- 
tion of the lunar orbit and of the motion of the nodes ; the 
observed accurate positions of a thousand fixed stars ; the 
explosion of the time-honoured error about the irregularity 
in the precession of the equinoxes (trepidatio) ; the accumu- 
lation of a vast mass of carefully planned observations of 
the planets in order to have new tables of their motions 
constructed ; and lastly, the observations of comets proving 
them to be much farther away from the earth than the 
moon. This was indeed a proud record of the twenty 
years' work at Hveen, and was sufiBcient to show the world 
that Tycho Brahe was worthy to rank with Hipparchus, 
Ptolemy, and Copernicus. 

After this review of his labours, Tycho prints a letter 
from the late Imperial Vice-Chancellor Curtius and several 
from Magini,' and a short abstract of a letter from Padua 
(of December 1592), "from a certain Doctor of Medicine 
then staying there " (he did not like to add, " of the name of 
Gellius "). From this it appeared that the Government of 

■^ Astr. inst. Meek, foL A. 6, and fol. D. vci-so. 

2 He divides his observations into "pueriles et dubitse" (at Leipzig), 
"juveniles et mediocriter se habentes" (up to 1574), and "viriles, ratae et 
certissimse" (from 1576). 

^ See above pp. 213 and 223. 


Tenice intended to send an observer to Egypt, and Tycho 
takes occasion to address a suggestion to the Venetians 
that they should cause the latitude of Alexandria to be 
redetermined, to see whether there had been any change 
in this quantity since the time of Ptolemy, as maintained by 
some, and he offered to assist them in this undertaking with 
instruments and advice. The book is then wound up with 
a description, with views and plans, of Uraniborg and 
Stjerneborg (to which he adds some remarks about the- 
necessity of a good site for an observatory), a map of 
Hveen, and a short account of his transversal divisions and 
improved sights.^ 

In the original edition of this book there was no en- 
graved port.rait of Tycho, but in several of the copies 
which he presented to distinguished or influential persons 
a portrait in water-colours is pasted on the back of 
the title-page. This portrait is much larger than any 
published portraits, and represents him bareheaded, very 
bald (with a small tuft of hair over the middlfe of the fore- 
head), and a very woe-begone countenance. It does not 
offer much resemblance to the well-known engraving by 
Geyn of Amsterdam of 1586, which appears in Tycho's 
Epistoloe and in the edition of the Progymnasmata of 1610, 
which represents him standing in a kind of arch on which 
the arms of the families of Brahe and Bille, and of the 
families connected with them, are suspended. This en- 
graving has been reproduced ia Gassendi's book.^ Another 

^ The figures in our Chapter V. are reduced copies oi Tycho's figures. 
The principal contents of the Mechanica are given in the introduction to 
Flamsteed's Hist. Cosl. JBrit, vol. iii., and the figures of the instruments are 
copied in the M^'moires de VAcad^ie for 1763. 

^ In the first issue of the Progymnasmata (1602) there is quite a different 
portrait, not resembling any other, but standing in the same arch. In Hof- 
man's Portraits historigues there is another engraving by Haas of Copenhagen, 
apparently a copy (reversed) of Geyn's, which is reproduced in Weistritz's 


portrait of Tyclio Brate, but of unknown date, was an oil- 
painting in the historical portrait gallery at Frederiksborg 
Castle, which was destroyed in the great fire of that castle 
in 1859.-^ In the letter (quoted above) which Tycho wrote 
to Rosenkrands from Eostock, he mentioned that he had 
ordered a painter to paint his portrait, and would send it 
to Eosenkrands when it was ready. This picture is pro- 
bably the same which in the following century was preserved 
in the library of King Frederick III., and in the corner of 
which was an emblematic design with the following in- 
scription : — 

" Stans tegor in solido, Ventus fremat, ignis & unda. 


Anno Mioxovii, quo post diutinum in patria 

Exilium demum pristine libertati restitutus fui 

Tyclio Brahe Ot. " ^ 

This portrait (or a copy of it) was found in England in 
1876, and now belongs to the Eoyal Observatory, Edin- 
burgh.^ A full figure portrait occurs in Barctti Eistoria 
Coelesiis, representing Tycho leaning on a large sextant; 
the face resembles the engraving by Geyn, and the picture 
is apparently copied from a water-colour drawing on parch- 
ment in a copy of Tycho's Progymnasmata in the Strahof 
Monastery at Prague.* 

Tycho was not content with issuing the description of' 
his instruments, but as the first volume of his book {Pro- 

1 There is a copy of this portrait in Friis' book, Tyge Brake (1871). 

' The first line ("I am protected, standing on solid ground, let wind, fire, 
and waves rage ") is evidently intended to express Tycho's trust in the future, 
notwithstanding the threatening aspect of the time. Ot. means Ottonides. 
The inscription is given in Resenii Inscriptiones Mafniemes, p. 335, Weistritz 
"■ P- 334i 3.nd identifies the picture. 

> It was first noticed by Dr. S. Crompton {Proc. Manchester Lit. and Ph. 
Soc, vol. vi., 1S76), and was in iS8i purchased by the Earl of Crawford, who 
in 1888 presented it with his great astronomical library and all his instru- 
ments to the Royal Observatory, Edinburgh. See frontispiece. 

* Tierteljahrsschrift der astron. GeseUschaft, xvi. p. 273 (18S1), Safarik. 


gymnasmata), in which the catalogue of 777 stars occurred, 
was still unfinished, he thought it desirable to distribute a 
limited number of manuscript copies of his catalogue of 
stars. It was probably for this purpose only that he had 
before leaving Hveen got a number of stars hastily observed 
in order to exhibit the places of a thousand stars, and not 
be inferior to Ptolemy with his 1028 stars. This cata- 
logue of longitudes and latitudes of 1 000 stars for the year 
1 600 was now neatly copied on paper or parchment by his 
assistants, and to it were added tables of refraction and 
precession, of the right ascension, and declination of a hun- 
dred stars for the epoch 1600 and 1 700, and a catalogue 
of longitude, latitude, right ascension, and declination of 
thirty-six stars according to Alphonso, Copernicus, and 
himself, for the sake of comparison.^ The lengthy intro- 
duction to this manuscript work was in the form of a 
dedication to the Emperor Eudolph II., dated the- 2nd 
January 1598.^ In this Tycho reviews the successive star- 
catalogues of Hipparchus and his successors down to and 
including " incomparabilis vir Nicolaus Copernicus," and 
he remarks that in reality nobody after Hipparchus has 
observed any great number of stars, but that Ptolemy, 
Albattani, Alphonso, and Copernicus had merely added pre- 
cession to the longitudes, which circumstance in connexion 
with the limited accuracy of the catalogue of Hipparchus, 
and the numerous great errors which had crept into it, made 
it desirable to have a new star-catalogue prepared, in which 
the positions of the stars were given with the greatest accu- 
racy now attainable. This Tycho had done, and offered it as 
a New Tear's gift to the Emperor. The catalogue and the 
printed book, Mechanica, were sent to the Emperor by the 
hands of Tycho's eldest son, who also was the bearer of a 

^ The three first-mentioned tables are printed in the Progymnasmata, 
" This introduction is printed by Gassendi, pp. 247-256. 


letter, dated 2nd Jaauary 1598, in wliicli Tyclio stated that 
lie had been obliged to leave his country and had come to Ger- 
many, where he hoped it might be granted him to complete 
his labours under the auspices of the Emperor.^ About the 
same time Tycho sent magnificently bound copies of the 
star-catalogue to the Archduke Matthias, to the Vice- 
Chancellor Corraducius, to Wolfgang Theodore, Archbishop 
of Salzburg,^ the Bishop of Liibeck, and to other influential 
men in Austria and Germany, to the King of Denmark, 
Prince Maurice of Orange,' Joseph Scaliger,^ Magini, Koplci-, 
two years later to the Elector of Saxony, &c. As already 
remarked, the Progymnasmata, which was not i^ublished 
until after Tycho's death, only contained yjy stars, but 
Kepler in 1627 published the thousand star-places in his 
TabulcB Rudolphinm ; while it is most significant that Longo- 
montanus, Tycho's principal assistant, in bis Astronomia 
Danica, only inserted the y/!^ stars, doubtless because he 
knew well how worthless the additional star-places were. 
The handsome manuscript volumes entitled " Tychonis Brake 
Stellarum octavi orbis inerrantiuin accurata restihitio, Wan- 
desburgi. Anno cioioiio," were chiefly intended as advertise- 
ments, and it would be perfect waste of time to collate the 
various copies with a view to correcting Kepler's edition.^ 

When Tycho sent a copy of this catalogue to King 
Christian," he probably also sent a letter to the king, of 

' Printed in Breve og Aktstyhher, p. 31 (from two draughts in the Univer- 
sity Library at Basle). 

° This is the copy which afterwards came into the possession of Gassendi, 
who gives (pp. 257-259) a list of remarkable discrepancies between star-places 
in it and in the Tab. Rudolph. 

' Astron. Jahrbuch fur 1786, p.. 216. 

* This copy is now in the University Library at Leyden ("Descriptio 
stellarum octavi orbis inerrantium "). There is a copy of the catalogue in 
the Bodleian Library, presented to a Venetian nobleman. 

' As suggested by Baily in his reprint of the catalogue, Mem. R. Astron. 
Soe., xiii. ; compare his Aeoount of the Rev. J. Flamstced, p. 368. 

" Now in the Royal Library, Copenhagen. In a letter from Henrik Raniel 


which a draught is now preserved in the University Library 
at Basle, dated the 7th February 1598.^ In this Tycho, 
after offering his congratulations on the king's marriage, 
remarks that the troubles which he had met with in the pre- 
ceding year were perhaps ordained by fate, since it was the 
third annus dimactericus (i.e., the twenty-first year), since the 
foundation of Uraniborg. He, however, thanked the king 
for not having impeded his journey when he found it 
necessary for his studies to go abroad, though he regretted 
that his letter from Rostock had not been found satisfac- 
tory ; but to show his feeling for his country and king, he 
now forwarded two books which had been recently completed. 
While Tycho in this manner paid his respects to the king, 
notwithstanding the want of consideration with which the 
latter had treated him, he did not hesitate to write to 
Valkendorf to try to obtain some arrears of rent still due to 
him. In this letter, dated the 28th May 1598, Tycho first 
thanks the Treasurer for all the kindness he has shown him, 
and for the help he has given the steward at Hveen, who 
had informed Tycho that he had in several cases concerning 
the tenants there been supported by the authority of the 
Treasurer. "If it were known how contrary and disobe- 
dient the peasants on that little land are, and what I have 
suffered from them all the time I lived there, and yet had 
patience with them, and been more kind to them than they 
deserve, then perhaps people would think differently about 
them than they have done." Tycho next asks the Treasurer 
to instruct the Governor of Bergen to order half a year's 
rent of the Nordf jord estate to be paid to him or his agent, 

to Sophia Brahe (of 20th September 1599) the former writes that he would 
have sent her the books, but had to ask the king first, and his Majesty had 
said that though he did not understand or care much about them, still he 
would keep them as they were presented to him by Tycho Brahe (Breve og 
Aktstykkei; p. 39). These books were ^losaihly the Mechanica and the Catalogue 
of Stars. 1 £reve og Aktstykhr, p. 34. 


as it is still owing to Mm ; and in conclusion he apologises 
for giving so mucli trouble, but lie expects everything good 
from Valkendorf , and is sure that the latter will help him in 
everything just, and right, and feasible. ■"■ The whole tone 
of this letter seems to show with certainty that Valkendorf 
cannot have been a declared enemy of Tycho's, as the latter 
was of too haughty a disposition to condescend to write so 
pleasantly to an avowed and open enemy ; but on the other 
hand, this does not prove that Valkendorf did not assist in 
depriving Tycho of his great endowments. 

Some time before this last appeal was dispatched to 
Denmark, Tycho had on the 24th March 1598 written to 
Longomontanus. He had heard from the Jesuit Monavius 
of Breslau that Longomontanus had arrived there and had 
had a look at "Wittich's books, and Tycho therefore wished 
to know whether there were any manuscripts among them, 
and whether they were to be sold. He also inquired 
whether Longomontanus had seen the recent slanderous 
publication of Reymers Bar, which was too far beyond the 
limits of decency to deserve a refutation ; still it might be 
well for Longomontanus to put in writing all he had heard 
from his colleagues at Hveen about that person and his 
doings, as he himself might have forgotten some of the 
circumstances through all the troubles he had met with. 
Finally, he desired Longomontanus to come to him at 
Wandsbeck as quickly as possible, as he had something 
very important to discuss with him, and if he had not 
sufficient money, he was to borrow some or pawn something, 
and Tycho would settle about it aftei-wards, and he would 
not detain him long, as he did not himself intend to 
remain long at Wandsbeck. He had Johannes Miiller from 
Brandenburg with him in charge of his observatory, but 
he hoped Longomontanus would not disappoint him, and 

^ This letter is printed in the DansJce Magazin, 3rd Series, iii. pp. 79-80. 


he miglit bring -svitla him a copy of Everhard's Uphemerides, 
.which he had seen mentioned in a Frankfurt book-list, but 
which could not be had at Hamburg.^ Gassendi suggests 
that Tycho may have wanted the help of Longomontanus 
to complete the chapter of the Progynmasmata on the lunar 
theory, where some sheets were still unfinished, while the 
recent eclipses had shown that this theory was still capable 
of further improvement. 

"While Tycho Brahe was living at Wandsbeck, his host 
not only tried to make his stay there agreeable,^ but also 
did his best to assist him in finding a permanent abode, and 
the pecuniary Support necessary to enable him to resume 
his labours on the same scale as formerly. Rantzov wrote 
to the Elector of Cologne, and asked him to use his influence 
with the Emperor in favour of Tycho, and to endeavour to 
interest the Austrian Privy Councillor, Barwitz, in the cause 
of the exiled astronomer. At the same time Tycho wrote 
himself to his friend Hagecius, and explained how he was 
situated, in order that the physician to the Emperor might 
speak to his master, and also enlist the sympathy of the 
Yice-Chancellor Corraduc. In order not to neglect any 
chance, Tycho also sent one of his disciples, Franz Teng- 
nagel, a native of Westphalia, to Prince Maurice of Orange 
to present copies of the Mechanica and the star-catalogue 
to the Prince, together with a letter from the author. The 
Prince answered that he would endeavour to persuade the 
States General to invite Tycho to settle in the Netherlands, 
and a similar answer was sent by the Advocate of Holland 

' Martini Everarti Ephemeridcs novce et exactcs 1590-1610 ex novis tahulis 
Belgicis. Lugduni Batav., 1597. 

^ In the Museum of Northern Antiquities at Copenhagen there is a watch 
which is said to have been presented to Tycho Brahe by Rantzov. It is 
oval in shape, has two dials, one for hours and one for minutes, and Tycho's 
name, arms, and the motto, " Qvo fata me trahunt, a.d. 1597," are engraved 
on the inner case. In the same m\iseum is a wooden easy-chair which is sup- 
posed to have belonged to T. Brahe. 


(or Grand Pensionary, as he was afterwards called), Olden 
Barneveld, to whom Tycho, as a prudent politician, had also 
written and sent his books. Joseph Scaliger, who five years 
before had been called to Leyden as a professor, also wrote 
that he would do his best, but he feared that the slow pro- 
cedure of the States General would deprive the country of 
so great an honour and himself of the pleasure of being 
associated with a great man. In the meantime the Em- 
peror had desired Oorraduc to answer Tycho that he would 
willingly receive him and see that he should want nothing 
for the furtherance of his studies. In the course of the 
summer Tycho not only learned this from Oorraduc, but 
also received a letter from Hagecius urging him to come to 
Bohemia as soon as possible, while the Elector of Oologne 
replied to Eantzov that he had every hope of Tycho's being 
well received by the Emperor, and added that if Tycho, 
against all expectation, should not find his work liberally 
enough supported by the Emperor, then he would himself 
promote it to the best of his ability. Tycho therefore, on 
the 23 rd August, wrote to Scaliger, sending him his books 
(even the unfinished one), and thanked him for his kind- 
ness, and assured him that he would not have been disin- 
clined to go to Holland, but that he had now been invited 
by the Emperor and would soon set out for Prague. But 
if this journey should not lead to the expected result, and 
the States would make him a liberal offer, then he would 
willingly come to them with his astronomical apparatus.^ 

Tycho was still at Wandsbeck on the 14th September 
1598, on which day he wrote to Duke Ulrich of Mecklen- 
burg to thank him for a letter of recommendation to the Em- 
peror, and to ask him to accept a copy of the star-catalogue, 

^ Gasgendi, pp. 156-157. In return for these books, Scaliger some months 
later sent Tycho a copy of his Conjectural et notes in Varronem, which Tycho 
gave or lent to Taubmann, Professor of Poetry at Wittenberg. Kastner, 
Gesch. d. Math., ii. p. 409. 


with the same favour with which he had received his book 
on instruments.''- Not long afterwards Tycho left Wands- 
beck with his sons, his students, and a few small instru- 
ments, leaving for a while longer his wife and daughters 
and the greater part of his luggage in the kind charge of 
his host, who, however, died on the 1st January following. 
He travelled himself as far as Dresden, where he learned 
that there was pestilence and dysentery at Prague, and 
that the Emperor had retired with his court to Pilsen ; and 
when he wrote to Corraduc to announce his arrival, the 
Vice-Chancellor, at the Emperor's command, requested him 
to remain at Dresden until the epidemic was over. From 
Dresden Tycho wrote on the 28th November to Magini, 
with whom he had held no communication for about seven 
years, and told him that he had not finished his book yet, 
as the theories of the planets were not yet complete. He 
also gave a short account of the cause of his leaving Den- 
mark, and added in a postscript that Tengnagel, who was 
the bearer of the, letter, would verbally communicate some- 
thing secret. This turned out to be that Tycho would like 
some Italian to write a eulogy of him, for which Magini 
two years later recommended Bernardino Baldi, who was 
going to write the lives of great mathematicians.^ 

Tycho did not remain long at Dresden, but preferred to 
spend the winter at Wittenberg, where he had still friends 
from his two former visits. In the first week of December 
I 598 ^ he went to Wittenberg with his sons and assistants, 
entered his own name and those of his two sons on the roll 
of students in the University,* and was lodged in the house 

1 Letter (in the archives at Schwerin) printed ia Friis, Tyge Brake, p 

2 Cartegglo inedito di Magini, pp. 217 and 230. Baldi's Ddle Vite de' Mate- 
matici was never published (Kastner, ii. 140). 

. ^ He observed the meridian altitude of the sun on the gth December at 

* Mullen Cimhria lilerata, vol. ii. p. 105. 

•272 TYCHO BRAKE. ' 

whicli formerly had belonged to Melanchthon, and now 
belonged to his son-in-law, Peucer, and where the physician 
Jessenius (Johannes Jessinsky) lived at that time. In the 
meanwhile Longomontanus had proceeded to Wandsbeck, 
but on his arrival he only found Tycho's wife and daughters 
there. He remained with them until Tycho's servant Andreas 
arrived with letters requesting them to set out for Witten- 
berg, upon which Longomontanus accompanied the ladies as 
far as Magdeburg, and then returned to Denmark, where he 
observed the lunar eclipse on the 3 i st January following in 
his native village. On the 3 i st December 1598 Tycho wrote 
to him in reply to a letter he had just received, in which 
Longomontanus had informed him that a printer at Ham- 
burg, who had been intrusted with the printing of the sheets 
relating to the lunar theory, had performed his task very 
badly, so that it would be necessary to do it over! again. 
Tycho therefore wrote that he would get it done at Witten- 
berg.^ He thanked Longomontanus for his attention to the 
ladies, and offered to supply him with means for studying 
at some German University until he had himself become 
quite settled at the Emperor's court. He also expressed his 
pleasure at hearing that Longomontanus intended to write 
a refutation of the so-called defence of the Scotch opponent, 
and he wished that it might be finished soon, so that it 
might be printed at Wittenberg as an appendix to the 
volume on the comet of 1577.^ On the iith January 
1599 Tycho again wrote to Longomontanus asking him 

' He afterwards abandoned this idea, because the eclipse of January 31, 
1599, did not agree with his theory, although he had expected that it should 
agree as well as that of January 1582, as they both took place near the apogee 
and at the same time of year. (Letter to Longomontanus of 21st March 1699, 
Gassendi, p. 159). This shows that he had at that time an idea of the exist- 
ence of the annual equation. (See next chapter.) 

^ We have already mentioned (p. 209) that this refutation was never pub* 
lished. It appears from a letter to Scultetus, written in January 1600, that 
Tycho was still thinking of adding an appendix to the book on comets. 


soon to come to Wittenberg at his expense, and offering to 
get him the professorship at Prague now held by Reymers 
Bar, who would doubtless soon make himself invisible ; or 
if Longomontanus would prefer a post at Wittenberg, 
Tycho would see that a professor there, who was not dis- 
inclined to go to Prague, was appointed to Reymers' post, 
and Longomontanus might then get the post vacated at 
Wittenberg. None of these proposals were, however, ac- 
cepted, and Longomontanus did not join his old master 
until the latter had been at Prague for some time.'^ 

It was not difficult for Tycho to foresee that Reymers 
would not care to await his arrival at Prague. When the 
former swineherd saw the expressions which Tycho and 
Rothmann had used about him in their letters, and which 
were made public by the printing of these, he naturally 
became furious, and in i 597 he published at Prague, where 
he had in the meantime become Professor of Mathematics, 
a book De astronomicis hypothesibus, in which he gave his 
fury full play.^ The title-page shows the motto (in Greek), 
"I will meet them as a bear bereaved of her whelps" 
(Hosea xiii.), and indeed the language of the author is bear- 
like enough. First he tells how he discovered the Tychonic 
system on the i st October 1585, and explained it to the 
Landgrave on the ist May I 586, after which a brass model 
of it was made by Biirgi, and he suggests that Tycho may 
have heard of it through Rothmann (or, as he calls him 
throughout the book, Rotzmann, i.e., Snivelman). After- 

' Gassendi, pp. 158, 159. 

^ " Nicolai Kaimari Vrsi^ Dithmarsi S. Caes. Maj. Mathematici de astrono- 
micis hypothesibus seu systemate mundano traotatua astronomicus et cosmo- 
graphicus scitu cum iucundus tum vtilissimus. Item astronomicarum hypo- 
thesium a se inuentarum, oblatarum et editarum contra quosdam eas sibi 
temerario vel potius nefario ausu arrogantes, vendicatio et defensio. . . 
Pragse Bohemorum apud auctorem. Absque omni priuilegio. Anno 1597." 
78 pp., 4to. Eastner, iii. p. 469. Delambre, 4s«}-. TOod, i. p. 294. I have not 
seen this book myself. 



wards lie maintains that Tyclio bad merely imitated the 
system of Apollonius of Perga, and that HelisEeus Roslin 
had recently with equal coolness claimed the same as his 
own.'"' He attacks Tycho and Eothmann with the coarsest 
abuse, and is very anxious to disprove that he was ever in 
Tycho's employment, as Rothmann had believed, and tells 
how he came to Hveen with Erik Lange. It appears that 
Tycho cut him short during a dispute with the remark that 
" those German fellows were all half-cracked," ^ and that he 
generally went by the appellation of " Erik's Dreng " (i.e., 
Erik's boy), and he adds proudly, " Jam non sum Jerix 
Dreng sed Imp. Eudolphi II. Mathematicus." To Tycho's 
accusation that Eeymers had stolen the idea of the new 
system during his stay at Uraniborg, he answers that in 
that case it would have been stolen from him again, since 
Tycho, before his departure, got somebody to search his 
papers at night, when nothing was found but some plans of 
the buildings. The only way he could ever have spoken 
ill of Tycho must have been by joking about his nose, of 
which the upper part had been cut off, and he indulges in 
some scurrilous remarks about the facilities which Tycho 
possessed for taking observations through his nose with- 
out sights or instruments. But other parts of the book, 
like the " Eundamentum astronomicum," ^ showed that 
Reymers was a very skilful mathematician, who deserves 
every credit for having by his own exertions, and appa- 
rently without enjoying the advantages of regular teach- 
ing, raised himself from the position of a swineherd to 

^ Helisasus Rcealinns in 1597 published a book, De opere Dei CreatffrU, in 
which he stated that he had independently found the same system as Tycho 
Brahe, and in a later publication he stated in detail how he did this after 
reading Ursus' book of 1588. (See Trisch in vol. i. p. 228 of his edition of 
Kepleri Opera.) 

^ Reymers writes this in broken Danish : " Den Tyske Karle er allsammell 
all gall" (should be : "de Tydske Karle ere allesammen halv gale"). 

^ See above, p. 183. 


that of a professor at Prague. It is easy to understand 
that his venomous attack must have been doubly annoying 
to Tycho at the particular moment when it was published 
and when he was anxiously seeking a new home. Tycho 
therefore began to collect evidence to show that his enemy 
had really behaved in a suspicious manner while at Hveen, 
and a document has been preserved, drawn up and signed 
before a notary at Cassel by Michael Walter, secretary to 
Reymers' former master, Lange. In this the writer states 
that Reymers, when Lange at his urgent request had con- 
sented to take him to Hveen, continued to poke and pry 
among Tycho's instruments and books whenever nobody was 
near, and to make drawings of everything ; that one of 
Tycho's pupils warned his master about this, and mentioned 
it to a certain Andreas ^ who then went to sleep at night 
in the room with Reymers, and while the latter slept took 
a handful of papers out of one of his breeches-pockets, but 
was afraid to search the other for fear of waking him ; that 
Reymers on discovering his loss behaved like a maniac, 
upon which he received back those of his papers which did 
not concern Tycho Brahe. The secretary also states that 
Reymers, after Lange's return to Bygholm Castle in Jutland, 
continued to behave more and more like a madman, and told 
everybody that Lange was going to hang him, until his 
master got tired of all this and dismissed him.^ 

Though it could not possibly be proved that Reymers 
had copied the idea of his planetary system from Tycho 
Brahe, it must be conceded that the latter had good reasons 
for suspecting him, even before he published his system in 
1588, and we must remember that the scientific men of 
the age were always afraid of being robbed of their dis- 
coveries, and often took great pains to secure priority by 

' Perhaps No. 5 on the list of pupils (Note B.). 

' This document is printed in Eepleri Opera, i. p. 230. 


hiding them in anagrams. But on the other hand, Eeymers 
certainly was an original thinker, and he may quite inde- 
pendently have come to the same idea which Tycho had 
already conceived. But the whole question is not of much 
consequence, and we have merely dwelt so long on it be- 
cause it attracted a good deal of attention at the time, and 
because the steps which Tycho afterwards took against 
Reymers throw considerable light on his own character. 

Having spent the winter I 598—99 at Wittenberg, where 
his family had joined him, Tycho was further delayed by 
the illness of his eldest daughter ; but shortly after Easter 
he at last set out for Prague, letting his family, however, 
stop for a while half way, at Dresden, until he had himself 
seen the state of things at Prague. 


The Germaa Emperor. Endolph the Second, whose service 
TTcho Brahe was now about to enter, was a man deeply 
interested in science and art, personally of a most amiable 
disposition, but most singularly unfit for the exalted and 
difficult position he had to fill. Totally devoid of energy 
and taking no interest in political matters, he let public 
affairs drift in whatever direction they liked, ignorant or 
careless of the fact that his apathy was hastening the 
catastrophe which a few years after his death plunged 
Central Europe into the war which turned Germany into a 
desert and almost annihilated the Imperial power. The 
times were certainly most serious, and the difficulty of 
settling the religious question almost overwhelming, but a 
monarch of spirit and determination might have done much 
to counteract the intrigues of the Spanish and Jesuitical 
party, who blindly pursued their narrow-minded policy, and 
finally brought on the Thirty Years' War. But, regard- 
less of the duties imposed on him by his station, the Em- 
peror reluctantly devoted a moment to business of any kind, 
while he w illin gly gave his time and the limited pecuniary 
means of his impoverished dominions to collecting art 
treasures and promoting science — the real science repre- 
sented by Tycho and Kepler, as well as the im^inary ones 

' In addition to Gasendi and Tycho's letters tj Tedel and Longomontanns, 
the sources for this period are : Frisch'a Vita Kepleri, in toL \-iii of Joh. 
Kepleri Opera Cmiiia, and Joseph r. Hasner, Tyeho Brahe und J. Keller in 
Prag. Eine Studie, Prag, 1S72. 


taught by the disciples of Cornelius Agrippa and Cardanus. 
Prague, where he usually resided, was not a very favour- 
able place for the growth of science and art, as Bohemia 
had never settled down since the Hussite disturbances. 
The Germans and the Czechs were sharply separated by 
race and language ; Catholics were opposed to Lutherans, 
Moravians, and Utraquists, the last-mentioned differing from 
the Catholics only by partaking both of bread and wine in 
the Eucharist. . But notwithstanding this state of things 
and the miserable condition of the University, Rudolph 
succeeded in bringing together a number of men of culture 
in Prague, and for a short time he made the city one of 
the centres of civilisation — a distinction which was un- 
fortunately destined to be but very short-lived. Long 
before his death, the Emperor's mind had been so persis- 
tently influenced by the intrigues of the Spanish party, 
that he had no feeling but distrust and suspicion for his 
surroundings, and scarcely felt relieved from the burden of 
government in the circle of his scientific friends. But 
while Tycho Brahe lived, Rudolph was still comparatively 
free from political anxiety, and ready to do his utmost to 
befriend the distinguished foreigner who had sought shelter 
under his roof. 

When Tycho arrived at Prague in June 1599, the 
Emperor sent the Secretary Barvitz to conduct him to the 
house of the late Vice-Chancellor Curtz, where the widow 
was still residing. He had only a few instruments with 
him, as most of those he had brought away from Hveen 
were still at Magdeburg. He was shortly afterwards received 
in audience by the Emperor, who welcomed him to Prague, 
begged him to let his family tjome from Dresden, and coii- 
versed with him for a long time in Latin. Tycho presented 
the Emperor with three volumes of his works, and was 
afterwards told by Barwitz that the Emperor often read in 


them till very late at night. As Tycho left it to the 
Emperor to fix the amount of his salary, it was settled that 
this was to be 3000 florins a year, in addition to some 
" uncertain income which might amount to some thousands." 
Tycho teUs aU this in a long letter to his old friend Tedel, 
which he wrote on the 1 8 th September following, in which he 
adds that some councillors were against these arrangements, 
pointing out that there was nobody at court, not even 
among counts and barons of long service, who enjoyed so 
large an income ; but as the Emperor insisted on it, and 
neither the Secretary of State, Eumph, nor the Chamberlain, 
Trautson, spoke against it, it was settled, and 2000 florins 
were at once paid to Tycho. The Emperor even ordered 
that the salary should date from the time when Tycho had 
been invited to Prague, as he had not accepted service else- 
where since then. The Emperor also of his own accord 
promised him an hereditary estate whenever one should fall 
to the Crown, in order that he and his family might feel 
secure.^ It was afterwards ordered that 2000 florins a 
year were to be paid to Tycho from the Treasury, and 1000 
from the estates of Benatky or Brandeis, both dating from 
the 1st ^ay 1599.' 

In the meantime Tycho had unpacked the few instru- 
ments he had brought with him, which were examined 
with great interest by Corraduc, Hagecius, and other men 
of learning, as well as by the Emperor, who desired him to 
send for the remainder as soon as possible. Wishing to 
display the same taste and elegance in his arrangements as 
formerly at Uraniborg, Tycho had a pedestal made on which 
instruments might be placed, and the four sides of this 

1 Bang's Samlinger, ii. p. 511 ; TTeiitritz, i. p. 175. 

- One florin {scAock meissn.) = 5 maik 81 pf. ; ICXK) florins therefore about 
jC^oo ; bat ttie value o£ money in Bohemia appears at that time to have been 
about four times as great as now. 


pedestal were adorned with, pictures of King Alphonso, with 
Ptolemy and Al Battani sitting below him ; Charles the 
Fifth with Copernicus and Apianus ; Eudolph the Second, 
and below him Tycho, seated at a table looking towards the 
Emperor ; and lastly, Frederick the Second with Uraniborg. 
Under the last picture was an epigram by the Imperial 

In his as yet unsettled state Tycho was not able to com- 
mence observations with the vigour of former days, the only 
observation of any interest made at this time being one of 
the end of a small solar eclipse at sunrise on the 22nd July 
(new style, which Tycho used from henceforth). One of his 
pupils, Johannes from Hamburg, observed this eclipse with 
the little gilt quadrant, from the tower of a neighbouring 

But Tycho did not wish to settle within the city of Prague. 
In his letters he states that he did not like that the widow 
of Curtius should leave her house for his sake, and he feared 

ft to be too much disturbed by visitors. Tradition speaks of 
his being annoyed by the constant ringing of bells at night 

' i in the neighbouring Capuchin monastery,^ but this may more 
probably refer to his stay in the city during the last year 
of his life, or it may never have happened ; at any rate, it 
is not mentioned by Tycho himself. But he was accustomed 
to a country residence, with plenty of fresh air, and he pro- 
bably longed to get away from the city, which was not very 
clean, if we may believe Fynes Moryson, who had visited it 
only seven years before Tycho's arrival, and who gives the 

^ Gassendi, p. l6i, where another poem composed on the same occasion is 
also given. 

^ Ibid., p. 162 ; Barrettus, p. 844. The quadrant is described above, p. loz. 
, s Madler, Pop. Astronomie, 1st edit., 1841, p. 561 (not in the latest edi- 
tions), and Heiberg, Urania, Aarbog for 1846, p. 131. According to another 
tradition, the monks did not like the neighbourhood of the heretic, and got up 
an apparition of a ghost to persuade the Emperor to turn him out. 


following description of it : — " On the west side of Molda is 
tte Emperour's castle, seated on a most high mountaine, in 
the fall whereof is the suburbe called Kleinseit or little side. 
From this suburbe to go into the city, a long stone bridge 
is to be passed over Molda, which runnes from the south to 
the north and diuides the suburbe from the city, to which 
as you goe, on the left side is a little city of Jewes, com- 
passed with wals, and before your eies towards the east is 
the city called new Prague, both which cities are compassed 
about with a third, called old Prague. So as Prague con- 
sists of three cities, all compassed with wals, yet is nothing 
less than strong, and except the stinch of the streetes driue 
backe the Turks or they meet them in open field, there is 
small hope in the fortifications thereof. The streets are 
filthy, there be diuers large market places, the building of 
some houses is of free stone, but the most part are of 
timber and clay, and are built with little beauty or art, the 
walles being all of whole trees as they come out of the wood, 
the which with the barke are laid so rudely as they may on 
both sides be seen." 

When the Emperor learned that Tycho Brahe wished to 
reside outside Prague, he gave him his choice between the 
three castles of Lyssa, Brandeis, and Benatky, " zur Exer- 
cirung seines Studii." Having seen them all, and having 
learned that Brandeis (which was situated rather low) was 
the Emperor's favourite hunting-lodge, Tycho selected 
Benatky on the Biver Iser (a tributary to the Elbe), about 
twenty-two miles north-east of Prague. The Castle of 
Benatky, which the Emperor had recently purchased from 
Count Dohnin, had been erected in 1522 in the place of 
an older castle which had been destroyed during the Hussite 
wars. It has since Tycho's time been considerably enlarged, 
so that the building inhabited by him now only forms the 

' Hradschin, where the house of Curtius was situated, west of the castle. 


western wing. The present cliurch tower is also a later 
addition. The castle is situated close to the town of NovS 
Benatky (in German, Neu Benatek) on the right bank of 
the Iser, on a hill raised about two hundred feet over the 
river. The castle commands a fine view of the vineyards 
and orchards on the hilly northern (right) bank and tilled 
fields and pasture-lands on the southern, which latter are 
not seldom flooded by the Iser, so that the inhabitants on 
such occasions are surrounded by a lake.^ This may account 
for the name of Venetiee Bohemorum by which Benatky has 
frequently been called, though Tycho believes that the 
general beauty of the surroundings has also contributed to 
the use of this name;^ On the way to Benatky, Tycho sent 
from Brandeis a letter to Longomontanus at Eostock, dated 
the 20th August, in which he mentioned that the road was 
level, and that the journey took about six hours ; an official 
from Brandeis was that day or the next to conduct him and 
his belongings to Benatky, where he expected to remain 
until he got the estate which the Emperor intended to 
confer on him in fief.^ As soon as Tycho arrived at 
Benatky he set about altering the building and construct- 
ing an observatory and a laboratory. As usual, he ex- 
pressed his pleasure at having at last found a resting- 
place in various Latin poems, two of which were inscribed 
over the entrances to the observatory and the laboratory.* 
The principal instruments were to be placed in separate rooms, 
as at Hveen, all connected with each other, and with the 
laboratory and residence, and a separate entrance was to be 

■'■ Description of Benatky by David. See Zach's Monatliohe Correspondenz, 
vi. p. 475 (1802). On the appended plate the wing in the centre and the 
church-spire were added after Tyeho'a time. 

^ Letter to Pinelli, Aus Tycho Brake's Briefwechsel, p. 12. Tycho always 
calls the place Benaoh. 

3 Gassendi, p. 163 ; Bang's Samlinger, ii. p. 501 (Weistritz, i, p. 164). 

* Gassendi, p. 164. 





made for the Emperor, who had reserved an adjoining house 
for his own use whenever he visited Benatky."^ '\MietlLer 
Eudolph ever came to Benatky while Tycho was there is 
not known, but it is not likely, as he was again in the 
autumn of 1599 driven from Prague to Pilsen by the 
plague, and did not return till July 1 600. Tycho also left 
home for the same reason towards the end of i599j ^^^ 
lived for six or seven weeks at an Imperial residence at the 
village of Girsitz, a few miles south of Benatky, where some 
observations were made in December." It was during this 
new visitation of the plague that the Emperor desired Tycho 
to give him the prescription for his " elixir " against epi- 
demic diseases, as already mentioned.^ 

In the meantime the family had arrived from Dresden, 
and as everything now appeared to promise Tycho that he 
had found a haven for the remainder of his days, he sent 
about the end of September his eldest son, together with a 
certain Claus Mule, to Denmark, to remove the four large 
instruments which were still at Hveen, and took this oppor- 
tunity of sending a number of letters to his family and 
friends. Among these letters was one to Talkendorf , asking 
him to facilitate the transport of the instruments,' one to 
his own brother, Axel, to the same purport, another to Longo- 
montanus, and a very long one to his old friend Tedel. In 
this he gave a very full account of his doings since he left 
Hveen, which he asked Tedel to incorporate in his Danish 
history, so that it might be handed down to posterity, 
whether printed or not.' Tycho's daughter Magdalene 

1 Lerter to Sophia Brahe in Breve og Alctstykker, pp. S5— S6. 

- Barrettui, pp. S50 and 856 ; Breie og AktstyUcr, pp. 9S ind loS. 

* See above, p. 13CX 

* The letter is not extant, but Tycho allndes to it in the letter to Longo- 
montanus (Gassendi, p. 167 ; "Weistritz, i. p. 186). The Emperor had directed 
Barwitz to \\ rite to the Danish Privr Counoilior, Henrik Kamel, on the same 

' This letter was published at Jena in 1730 (23 pp. 4to) by G. R Casseburg, 


sent a letter to Claus Mule's mother, in whicli she also 
described the travels of the family .1 To his kinsman Eske 
BUle, who seems to have done his best for Tycho in the 
way of executing commissions and looking after his ai&irs 
at Hveen and elsewhere in Denmark, Tycho also wrote on 
this occasion. Bille had some months before sent him 700 
daler, which however did not reach Prague till a short time 
before Christmas, and he was to receive some money which 
Tycho's cousin, Axel Gyldenstjeme (Governor of Xorway), 
owed him ; and on the other hand, he was to pay 5000 
daler which Tycho owed to the widow of Heinrich Eantzov, 
which he did in the course of the year 1600.^ Tycho's son 
got the iiLstruments at Hveen dismounted and sent by sea 
to Liibeck, after which he returned to Bohemia, where he 
arrived in January 1600 with a supply of salt fish from 
Hveen, which island Tycho continued to hold in fee till 
his death. He was also the bearer of a great many letters 
from relatives and friends — among others, of one from 
Tycho Brahe's aged mother. 

At that time the instruments were still at Liibeck, pro- 
bably because Tycho's agent there was nnable to get them 
sent on to Hamburg, where they did not arrive till the 
following April. On the 8th September 1599 the Em- 
peror had written to the Burgomaster and Senate of Ham- 
burg, desiring them to forward the instruments by ship on 
the Elbe, and Tycho himself had written to them on the 
29th September, requesting them to get the instruments 
under way before the Elbe froze over, but these letters were 

Tycfu/nii Brdtie Edalio de ilatu gwj post, disceseum ex jMbria, and more 
accurately in the hdnitche B'MiMhek, iii. 1740, y. iSo ei geq. Translated in 
WeirtritZ; L p. 169 et teq. 

^ I/ariike iloyizin, ii p. 359 ; Weiirtritz, ii. p, 365. C3an-! Mole wag a wm 
of the Bur^oma-ter of Odeniie in Denmark. A letter from Tycho to bim (ap- 
parently written while Kale waa abroad, perhaps at Eoatock, 33 it allndes to 
Professor Caijelios) ia quoted abore p. 240, footnote. 

' BriTK og AkUstyhker, pp. 50, 37, 93, loi, 1 17, 14S. 


not read in tlie Senate till the 2 1st April following, when 
tlie agent at Llibeck had at last forwarded tke instru- 
ments to Haniburg.i A similar delay occurred -with the bulk 
of the instruments, books, &c., -which Tycho had himself 
brought from Denmark as far as Magdeburg. About the 
transport of these to Prague by the Elbe the Emperor had 
also written in September 1599 to the civic authorities at 
Magdeburg, and he wrote a reminder to them some time 
after ; but the Town CouncU coolly replied that they were 
unable to do anything, and, among other excuses, they 
mentioned the great damage done to the town when the 
celebrated Elector Maurice of Saxony, as commander of the 
Catholic forces, had besieged it some fifty years before. 
Having, to the disgust of his Austrian councillors, swallowed 
this affront, which showed how little the Imperial authority 
was respected in the North of Germany, Eudolph addressed 
himself to the Chapter of Magdeburg, and Tycho forward- 
ing this letter by a servant of his in April 1 600, also wrote 
to the Chapter begging them to help him in the matter." 
It appears from a letter which Tycho wrote in September 
1600 to Duke Otto of Brunswick (who wanted his horo- 
scope prepared) that the instruments and books had then 
only got as far as Leitmerits, in Bohemia, and in November 
1 600 Tycho wrote to Landgrave Maurice that he had at 
last got all his twenty-eight instruments at Prague.^ But 
he had then long ago left Benatky. 

"While the instruments were on their way to Bohemia, 
Tycho was endeavouring to push forward the alteration of 

1 The two letters (in the city archives of Hamburg), printed in Friis, Tj/ge 
Brake, pp. 320 and 324. Letter from Tycho to Vincent Miiller, Burgomaster 
of Hamburg, of April 24, 1600, in JSreve og AitstyHer, p. 125. 

^ Tycho's letter to the Chapter, Aus Tycho Brake's Bnefiaechsel, p. 21 ; 
compare Breve og Akt^fyk^er, p. 114- 

' Brn-e og Altstyll-er, pp. 141 and 143. Tycho -nrote to Eske BiUe on 
November 16, that on looking over his things, he noticed that some articles 
were missing which might still be at Copenhagen or at Ltibeck. Ibid., p. 140. 


Wittenberg. He also hoped that David Fabricius, from 
Ostfriesland, whom Longomontanus had met at Wandsbeck, 
would come to act both as domestic chaplain and as observer ; 
and he was getting two students from Wittenberg, who had 
offered themselves through Jostelius, as he hoped to start 
again an astronomical school for the benefit of posterity and 
for the glory of God and the credit of the Emperor. Pos- 
sibly Christopher Rothmann would also come, as he had 
recently written to EoUenhagen of Magdeburg (a well- 
known writer on astrology and many other things), so that 
he was not dead, as Tycho had for some time believed ; but 
that bear-like and Dithmarsian brute (ursina ista et Dithmar- 
sica bestid) had told a double lie when he had spread the 
rumours that Tycho had fled from Denmark for some great 
act of villainy, and that Rothmann had died from debauchery. 
The same Reymers had secretly absconded lately from Prague, 
but he would yet meet the punishment he deserved.^ The 
sheets which were still wanting in the first volume of the 
ProgymTiasmata, and which the Hamburg printer had done 
so badly, were soon to be printed, and when Longomontanus 
came, all might be settled, so that the book might be issued 
together with the second volume (on the comet of 1577), 
while the third volume on the other comets might follow.^ 

Several of the collaborators whom Tycho in this letter 
hoped to secure did not put in an appearance. Longomon- 
tanus arrived in January 1 600 with Tycho's son,' but Roth- 
mann never came ; Pabricius only came in June 160 1 for a 
couple of weeks,* and Miiller did not arrive till after March 

^ In the letter to Vedel, Tycho also mentions this, and adds that Eejmers 
had left his wife behind, who (of course) enjoyed an evil reputation. 

2 In January 1600 Tycho inquired from Seultetus whether the printing 
could not be done at Gorlitz {Aus Tycho Brake's Briefvieehsel, p. 16). 

' Kepleri Opera, viii. p. 7 1 5. 

^ Apelt, Die Reformation der Sternhunde, p. 271. Tabricius went with a 
message from the Count of Ostfriesland to his envoy at Prague. A letter 
which he wrote to Kepler from Prague is printed, Opera, i. p. 305. 


1600/ and left again in the spring of 1 60 1, after wliicli he 
disappears from the history of science altogether. But in 
the meantime negotiations had been entered into with a far 
greater man than any of these, which terminated in the 
removal of Kepler from Gratz to Prague, an event which 
prpduced the happiest results. 

'^"Johann Kepler was born on the 27th December 157 I, at 
Weilderstadt, in Wiirtemberg, and studied from i 589 at the 
University of Tiibingen under the talented mathematician 
Michael Mastlin, through whom he became acquainted with 
the Oopernican system, and convinced himself of its being 
the only true representation of the planetary system. He 
completed his studies in the faculty of Arts, and took the 
Master's degree in 1 59 1, after which he entered the theo- 
logical faculty, and spent the next two years in studying the 
intensely narrow-minded dogmas which then prevailed in 
the Lutheran Church, and which were so distasteful to him 
that he was soon known among theologians as one unfit for 
a clerical career. When, therefore, in 1594 the post of 
" provincial mathematician " of Styria was offered to him, 
he was urged by his friends to accept it ; and though he 
hesitated somewhat, as he had not particularly devoted him- 
self to the study of mathematics, he yielded in the end, as 
it might not be easy for him to find suitable employment 
in Wiirtemberg, while the lively intercourse between the 
numerous Protestants in Styria and their co-religionists at 
Tiibingen helped to bridge over the distance of Gratz from 
his home. In Gratz the young professor lectured less on 
mathematics than on classics and rhetoric, while from 1594 
he prepared annual -calendars, with the usual meteorological 
predictions and hints on the political events of the coming 
year. In 1596 his first great work appeared, Prorfromws 
Dissertationum Cosniographicarum continens Mysterium Cos- 

' Breve og Ahstykker, p. no. 



racgraprdcuTii, in whicli he se: forth a relation, between the 
fire regular poljhedra and the distances which then were 
assumed between the planets and the sun ia the Coper- 
nican system. The genius of the writer was conspicao:is'.v 
displayed in this book and at once attracted attention. 
Kepler had already in ZSovember 1595 addressed a letter to 
Eeymers, ia which he explaiued the ideas contaiued iu his 
forthcoming work, but the " Ca^arean mathematician " tc-ik 
no notice of the letter of tlie unknown young man until 
June 1597, when he had probably heard the b>jk well 
spoken of, and wrote to Kepler Vj ask for a copy.i In the 
mad book which he published in the same year, Ee^iLers 
inserted Kepler's letter of if 95, at which Tycho did not 
feel particularly pleased, though he Lad sense enough to 
acknowledge that Kepler had merely been ciril to a man 
wtom he only knew through his scientific writings. In a 
letter which Tycho wrote from Wandsbeck on the 1st April 
1593, to thank him for a copy of the Prodromus ^whicli 
Kepler had recently sent with a respectful letter), he 
expressed himself to that eSect. At the same time he gave 
due praise to the ingenious speculations of Kepler, though 
he had some dotibts as to the numerical data employed, &i.q 
of course he could not help regretting that the Ck)pemican 
system was the fotindation on which Kepler had built. He 
expressed, however, the hope that Kepler would yet adopt 
something similar to the Tycaonic system, which made 
Kepler (who throughout furnished the letter with marginai 
notes) remark : "' QuUiid se amat." ' .Shortly afterwar-ds Tycho 

- XTrFOE h^i just p-iblisted a work on liaciasAagj, CkroaatiA^trvm. mt 
Theatram tempzirii annonaa 4000, ■ f wiicn he s^iit Eejl4r a copv with tia 
ler^ir ite fiH T.S.- is given by Haniscb, EpUt. ad I. Keplenai, p. 90 ; n es-k 
be an eitremelv scarce book). Kex'.er was so lirtle aware 0: ihe annSr 
between Tycho and UrF:is th^i he even s^ke I Uisn^ to forward a C[^ ot li6 
J'rodromiu to Tycho [Opera, L p. 233'. 

' E^'xA. K'-J.tri, p. IZ2 ; Opera, Lp. 43 ani p. ;Ij ; Ketler'sinireisalE:-^^ 
f . 119. 


also wrote to Mastlin (to whom he had ten years previously 
sent his book on the comet of 1577 without hearing from 
Mastlin since then), and repeated some of the doubts he 
had already expressed to Kepler.^ The latter was, however, 
not discouraged by these doubts, and wrote to Mastlin that 
he could in no way accept the Tychonic system, and that 
Tycho had abundance of riches which he did not use properly, 
as was generally the way with rich people, and it would be 
well to extort his riches from him by getting him to publish 
all his observations.^ To Tycho himself Kepler addressed 
a letter in which he, with manly and unaffected eloquence, 
protested against the crafty use which Reymers had made 
of his complimentary letter, which he had written simply 
because he had read Eeymers' Fundamentum astronomicum 
with much profit, had been advised by some Styrian noble- 
men to make a friend of this man on account of his influ- 
ential position (though they called him a new Diogenes), 
and had felt a desire of communing with a mathematician, 
since there were none in his own neighbourhood.^ The 
whole letter evidently made a good impression on Tycho, as 
Kepler's open and noble mind is reflected in every line, and 
Tycho wrote in reply that he had not required so elaborate 
an apology. 

The literary intercourse which had thus been opened 
between Tycho Brake and Kepler was soon to become a 
personal one. The very numerous Protestants in Styria 
had hitherto been perfectly unmolested by their Catholic 
rulers, but during a pilgrimage to Loretto which Archduke 
Ferdinand (afterwards the Emperor Ferdinand II.) under- 
took in 1598, he vowed to root out the heretics from his 
dominions, and on the 2 8th September all preachers and the 
teachers at the Gymnasium of Gratz were ordered to leave 

1 Opera, i. p. 45 et seq. ' Ibid., p. 48 et seq. 

' Ibid., p. 220 et seq.; Epist. ed. Hanschius, p. io5. 


tlie town before sunset. Kepler had to leave tis family (he 
Lad eighteen months before married a young widow, who 
was the mother of a girl seven years old) and depart for 
Hungary. He was, however, recalled within a month, as 
some of the Jesuits were much interested in his scientific 
work, and hoped that he might be persuaded to change his 
faith. He soon saw that he could not hope to be left 
in peace very long, and he made vain attempts to obtain 
some employment at Tiibingen. Mastlin was, however, 
unable to help his former pupil, and Kepler saw no other 
opening elsewhere. Meanwhile Tycho had been invited to 
Prague, and Kepler, who had already been anxious to meet 
him, was now more than ever desirous of doing so, and 
thought of undertaking a journey to Wittenberg for the 
purpose of conferring with Tycho. In August 1599 he 
learned from Herwart von Hohenburg, Chancellor to the 
Duke of Bavaria, who was a correspondent of Kepler's, and 
had frequently consulted the rising astronomer on matters 
connected with chronology,-'^ that Tycho had arrived at 
Prague and was to have a salary of 3000 florins. Herwart 
ended the letter by saying, " I wish you had such a chance, 
and who knows what fate may have in store for you." 
Kepler now consulted a number of friends and some men 
of influence at Prague, among whom was Baron Hoffman, 
a privy councillor who was well acquainted with Tycho, but 
who would at first give only an evasive answer. The most 
sensible advice was given by Papius, a physician, who had 
been obliged to leave Gratz as a Protestant, and was then 
practising his art at Tiibingen. He suggested that Kepler 
should make all possible inquiries at Prague about the con- 

^ Tycho had also for some time corresponded with Herwart, to whom he, 
on the 31st August, wrote a letter explaining his lunar theory, and particularly 
the calculation of eclipses. About this letter and Herwart's answer, see 
Gassendi, p. 165. 


ditions on wliicli lie might become associated with Tjcho, 
and that he should let his literary productions be shown 
at Prague in order to pave the way for him there.^ The 
latter part of the advice was certainly superfluous, and Tycho 
himself was more than willing to accept Kepler's services. 
In a long letter which Tycho wrote from Benatky on the 
9th December i 599, he expressed his hope of soon meeting 
Kepler, though he did not wish that the latter should be 
driven to him by misfortune, but by his own free will and 
his love of science, and he assured Kepler that he would 
find in him a friend who would always stand by him with 
help and counsel.^ 

Tycho's letter did not find Kepler at Gratz. He had 
at last made up his mind to examine the state of things 
at Prague with his own eyes, and, encouraged by Baron 
Hoffmann, he started with this nobleman from Gratz on the 
6th January 1 600, and arrived at Prague about a fort- 
night later. On the 26th Tycho wrote to Hoffmann that 
he had with great pleasure heard of their arrival, and 
thanked Hoffmann for being the means of introducing Kepler 
to him. Tengnagel (who had just returned from his home 
in Westphalia) and Tycho's eldest son were the bearers of 
this letter, as well as of another for Kepler, in which Tycho 
apologised for not welcoming him in person, but he rarely 
went to Prague except when called by the Emperor ; the 
oppositions of Mars and Jupiter were now to be observed, 
and the other three planets and a lunar eclipse likewise, 
so that he did not like to interrupt his work, but he would 
receive Kepler, not as a guest, but as a dear friend and 
colleague.^ On the 3rd February Kepler arrived at Benatky 
with a civil answer from Hoffmann, warmly recommending 

^ Kepleri OperOj viii. p. 709. 

^ Epist. ed. Eanschius, p. loS et seq. ; Opera, i. p. 223 and p. 47. 

^ Kepleri Opera, viii. p. 716; Aus Ti/cho Brake's Briefwechsel, p. i8. 


him to Trcho.^ "VTithin a few davs some preliminaiy 
arrangements were made witli regard to the distribution 
of work loetween the various assistants. Tycho's younger 
son, Jorgen, was to have charge of the - laboratory ; Longo- 
montanns had the theory of Mars in hand ; Kepler at first 
had to put np with the promise of the next p]anet which 
was taken np, but afterwards Mars was intrusted to him, 
as he was particularly eager to attack this most difficult 
planet, while Longomontanus undertook the lunar theory." 
But though Tycho was most cordial to Kepler, he did not 
enter very much into learned discourses, so that Kepler had 
often to coax him into answering some question while they 
were at table. He had a feeling that he was not looked 
upon as a man of recognised scientific standing, but merely 
as an ordinary assistant to the world-famed Tycho Brahe, 
and yet he felt that he ought to have full access to the 
great treasure of observations which Tycho possessed. In 
a document which Kepler drew up for the information of 
his friends,^ he remarks that Tycho had hitherto, by the 
magnitude of his undertakings, been prevented from dis- 
cussing his observations, and now that old age was approach- 
insr and soon would enervate him, he would hardlv be able 
to undertake that great work himself If the journey from 
Gratz was not to have been made in vara, either Tycho 
should allow him to copy the observations, which he doubt- 
less would refuse, since they were his treasure to which he 
had devoted aU his life, or he should admit Kepler to a 
share in the working out of the results from them. And 
the Emperor should do as King Alphonso had done, and 
associate others with Tycho. He himself ran the risk of 
losing his post at Gratz, for if Tycho took offence at some- 

^ Opera, pp. 716, 717; Brkfwcchid, p. 19. 

- Kepler, De Sldla Martis, chap. vii. (Opera, iiL p. 210). 

' Opera, Tiii. p. 718 rt seq. 


tiling in Bohemia and went away, or if something happened 
to him, what would then become of himself (Kepler), and 
perhaps the observations would be lost or become inacces- 

Influenced by these considerations as well as by the 
possible diflSculty of getting the consent of his wife's rela- 
tions to her removal from Gratz, where she had a small pro- 
perty near the town, to Benatky, where she would have to 
live among foreigners, Kepler drew up several different pro- 
posals for a formal agreement with Tycho Brahe, in which 
he most carefully tried to secure his future position, both as 
regards the lodging of his family at Prague, or at least in an 
upper storey at Benatky, with separate kitchen, supply of 
fuel and victuals, &c., as also with regard to his scientific 
work.'^ He added that he would not be content with general 
promises, which was a rather superfluous remark, since the 
minuteness with which he had specified his demands made 
this very evident. On the 5th of April the matter was dis- 
cussed verbally between Tycho and Kepler in the presence 
of Jessenius of Wittenberg, and in answer to Kepler's 
written demands, Tycho partly read himself, partly let 
Jessenius read, a written answer which followed Kepler's 
demands point for point.^ Tycho took the whole matter far 
more quietly than might have been expected from a man of 
his hot temper and imperious ways, but though he offered to 
bear part of Kepler's travelling expenses, and to do his 
utmost to get him settled at Prague (if he absolutely wanted 
to live there), or in a separate house in or near Benatky, he 
was unable to guarantee anything about salary or the keep- 
ing open of Kepler's Styrian post, until he could communi- 
cate with the Emperor and with Corraduc and Barwitz. 
Though Tycho begged Kepler to wait until his servant 
Daniel came back from Pilsen with replies to letters which 

' Opera, viii. pp. 721-724. 2 ibid.^ p. 725. 


Tycho had written to Corraduc, Kepler refused to listen to 
reason, and left Benatky the following day with Jessenius to 
return to Baron Hoffmann at Prague.^ 

There had evidently for several weeks been some mis- 
understanding between the two astronomers, as Tycho 
already, on the 6th March, had written to Hoffmann that 
as soon as he could find time from other occupations, they 
would both drive to Prague to discuss with Hoffmann the 
question as to Kepler's position. It cannot, however, have 
been Kepler's uncertain prospects alone which brought about 
the crisis on the 5 th April, for it appears that Kepler on the 
following day wrote a very violent letter to Tycho, of which 
the latter took no notice beyond sending it to Jessenius.^ 
It seems, therefore, probable that Kepler, as we hinted 
above, felt himself treated too much as an inferior and a mere 
beginner, while he, conscious of his genius, expected to be 
regarded as an independent investigator. Tycho, however, 
always expressed himself most kindly of Kepler in his letters, 
and it probably never occurred to him that he ought not to 
place Kepler on the same footing as his assistants. He now, 
on the 6th April, wrote a short letter to Hoffmann, in which 
he referred him to Jessenius for information as to the differ- 
ence between Kepler and himself, and expressed the hope 
that Hoffmann, with his prudent advice, would endeavour to 

' Among the Kepler MSS. in the Hof bibliothek at Vienna ia a declaration 
written and signed by Kepler on the 5th April 1600, in which he, having been 
hospitably received by Tycho Brahe, "auch diesegantze zeifc vber aller miig- 
licheit nach also tractirt worden, das ioh raich hingegen iederzeit, zue aller 
Vnderthaniger Danckbarkheit schuldig erkhennen " — pledges himself to keep 
secret all observations or inventions which Tycho Brahe had communicated or 
might communicate to him. (ITriis, Tyge Brahe, p. 327). This MS. is not 
mentioned by Frisch. If the date is correctly given, this document may have 
been an attempt on Kepler's part to conciliate Tycho, in order that the latter 
might make some concession as to the scientific work. 

' Kepler's letter is only known from Tyoho's letter to Jessenius. Opera, 
viii. p. 728. In this letter Tycho asks Jessenius to find out whether Kepler 
had now taken up with Reymers Bar, who had returned to Prague. 


settle the matter. He was not disappointed, for the remon- 
strances of Hoffmann, who was anxious to see Tycho and 
Kepler co-operate in the service of science, succeeded in 
softening Kepler, to which Jessenius, as a friend of both 
parties, also contributed. About three weeks after his de- 
parture from Benatky, Kepler therefore wrote a repentant 
letter to Tycho, in which he acknowledged that he had met 
with nothing but kindness from Tycho, and begged to be 
forgiven for his conduct, which was the result of a youthful 
and choleric temper and his shaken health.'"' The two 
astronomers met at Prague, were reconciled, and went back 
to Benatky together, where Kepler now stayed four weeks, 
until at the beginning of June he left Bohemia for a while to 
settle his affairs at Gratz. At parting, Tycho gave him a 
most flattering testimonial, in which he spoke in the highest 
terms of the manner in which Kepler had devoted himself 
to scientific work at Benatky.^ 

Kepler had hoped to be able to retain his appointment at 
Gratz and get leave for a year or two to work with Tycho. 
To settle permanently with him he was not inclined, but he 
soon had very little choice in the matter. Early in August 
an Ecclesiastical Commission arrived at Gratz, and every 
official had to appear before it and to state whether he would 
become a Roman Catholic or not. Those who refused were 
ordered to dispose of their goods and to leave the Austrian 
provinces within forty-five days. Among these was Kepler, 
who again applied to Mastlin and Herwart for advice. 
But at Tubingen there was no opening, and Herwart 
strongly advised him to go to Prague. There seemed to 
be no help for it now, and no matter what doubts Kepler 
might have as to the feasibility of living in the same house 
with Tycho and his family, or of preparing planetary tables 
in concert with a man from whom he differed on the most 

' Opera, viii. p. 729. - Ibid., p. 730. 


fundamental questions, lie had no choice but to go to 

In the meantime the Emperor had returned from Pilsen 
to Prague in July i6oo, and about the same time, or 
shortly afterwards, Barwitz advised Tycho to leave Benatky 
and move to Prague, as the Emperor would like to have his 
astronomer near him. Probably Tycho was not sorry to 
leave Benatky, where he and Miihlstein still kept up a 
running fight about money matters and building operations. 
He therefore left Benatky and took up his quarters tempo- 
rarily in the hotel Beim goldenen Oreif, on the Hradschin,' 
while his instruments were placed in Ferdinand I.'s viUa, 
not far from the castle.^ A few days after his arrival, 
Tycho was received in audience by the Emperor, who con- 
versed with him for an hour and a half. The Emperor 
inquired about Tycho's work, upon which Tycho remarked 
that he necessarily required more help, and suggested that 
Kepler might be attached to the observatory for a year or 
two. The Emperor nodded his consent to this, and desired 
Tycho to mention this proposal in a memorial about his 
requirements, which was to be sent to Barwitz. Tycho 
afterwards spoke to Corraduc, and asked that the Styrian 
authorities might be requested officially to give Kepler leave 
of absence for two years, and let him retain his salary, to 
which the Emperor would add a hundred florins on account 
of the expense of living at Prague. Tycho wrote to Kepler 

^ Hasner, p. lo. The house " Zum goldenen Greif " is still in existence 
(Neuweltgasse, No. 76), but is no longer an inn or a hotel. This quarter of 
Prague was then the most aristocratic one, being close to the castle. It was 
thoroughly devastated by the Prussians in 1757 by bombardment, and has 
since been the poorest part of the city. 

' Now called the Imperial Belvedere. On January 24, i6oi, Tycho wrote 
to Magini that he had now all his twenty-eight instruments " non longe ab 
Arce, in Oaesaris quadam magnifice extructa domo." Carteggio, p. 241. The 
observations at Benatky had been stopped at the end of June 1600, and they 
were not resumed till the 2nd December, " in domo Csesaris horto vioina ubi 
instrumenta mea adbuc disponebantur." Barrettus, p. 860. 





on the 2gth. August, and gave him an account of all this, 
and as Tycho's removal from Benatky to Prague promised 
to do away with some of the difficulties, Kepler, though 
still hesitatingly, set out for Prague early in September. 
Troubled not only by his anxiety for the future, but also by 
an intermittent fever which clung to him for nearly a year, 
he left most of his luggage half-way at Linz, in case he 
should yet want to go to Wiirtemberg. Ill and miserable, 
he arrived with his family at Prague in October, and was 
hospitably received in Hoffmann's house. His first com- 
munication with Tycho was by a letter (on the 1 7th Octo- 
ber ^}, in which he wrote that his hopes of retaining his 
Styrian salary were now at an end, and their former agree- 
ment consequently also ; but as Tycho had laid the matter 
before the Emperor, he had thought it best to come. He 
had, however, very little money left, and could only wait 
four weeks, and if his position at Prague could not be made 
secure within that time, he would have to look out for him- 
selt elsewhere. 

Tycho was much pleased to see Kepler return to Prague, 
the more so as he had lost his most experienced assistant, 
Longomontanus, who had wished to return to Denmark, and 
had received his discharge on the 4th August, when Tycho 
at parting gave him a very kind letter of recommendation.' 
It took a long time to get the question about Kepler's 
salary settled by the Government, but he and his family 
soon removed from Hoffmann's to Tycho's house, and he 
began work. This was probably not until the Emperor had 
purchased Curtius' house from the widow for 10,000 thaler, 

1 Opera, viii. p. 732. 2 Ibid., pp. 734-737. 

2 Printed by Gassendi, p. 174. In 1603 Longomontanus became head- 
master of Viborg school, in Jutland (where he had been educated himself) ; 
in 1605 Professor at the University of Copenhagen ; in 1607 Professor mathe- 
matum superiorum. He died in 1647, before the University Observatory on 
the Round Tower (which existed till 1861) was finished. 


and Tycho Lad taken possession of it, wliicli he did on the 
2Sth February i6oi.^ Kepler still could learn nothing 
about his salary, and continued, though in vain, to look 
out for an appointment in Germany, while Tycho now and 
then helped him with money. His health also gave him 
cause for anxiety, as he could not get rid of the intermittent 
fever, and early in 1 6o I he was troubled with a bad cough, 
which even made him fear that he was consumptive. In 
April he was obliged to go to Gratz to arrange some affairs 
connected with his wife's property, whence he did not return 
until August, having failed to accomplish his object, but 
having recovered his health. A curious letter has been 
preserved^ which Kepler's wife wrote to him on the 31st 
Jlay, in which she tells him that Johann Miiller had left 
again ; that Tengnagel had not yet given her any money, 
but that he and Tycho were friends again, and that his 
wedding (with Tycho's second daughter, Elisabeth) was to 
take place a week after Whitsuntide.^ This cannot have 
been the first complaint Kepler received from his wife about 
her getting no money, for he had already on the 30th May 
written an indignant letter to Tycho, blaming him for not 
having given her the twenty thaler which had been 
promised. Tycho did not trouble himself to answer this, 

' Gassendi, p. 176. The site of Curtius' house on the Loretto Place is 
uow occupied by the Cernin Palace. Canon David determined the geogra- 
phical position, lat. +50° 5' 28", 32° 3' 37" east of Ferro. In 1S04-5 an 
old tower was pulled down, which probably had been part of Tycho's obser 

= Opera, viii. pp. 739-741. 

^ "Der hanss Miller ist den 29 Mai mit seiner frau darvon vnd haim, der 
diho Prei (Tycho Brahe) hat jm abgefortigt vnd hat jm goben was er jm hat 
zuegesagt, aber vom khaiser ist jm khain heler nit worten. Der Diho hat jm 
sein hantl verdorbt beim khaiser er het sonst woU ein guette Verehmng 
bekhuineu so hat ehr de.s Diho miiessen engelten. Der franz (Tengnagel) vnd 
der Diho siut witer einss sie rihten ietz zu der hochzeit zue, der franz hat 
mier noh khein gelt gbben." . . . Miiller left on the 26th, according to a letter 
from Eriksen to Kepler (Ejpistolm, ed. hanschius, p. 176). 


but let one of his pnpils, Jobannes Eriksen/ write to 
Kepler that he had unasked, through his daughter, promised 
her ten thaler soon after Kepler's departure, which she 
also got on asking for them, and when she a fortnight 
later again requested ten more, Tycho sent to her by 
Eriksen sis thaler and promised her more, though he had 
not much cash at the time. All this he had done without 
grumbling, and both he and his family had been kind and 
obliging to Kepler's wife and her daughter. Tycho therefore 
desired Eriksen to beg of Kepler to have more confidence in 
him, and to conduct himself in future with more prudence 
and moderation towards his benefactor, who had been very 
patient with him, and wished him and his well.^ This 
letter had probably the desired effect, and Kepler, who at 
heart was most generous and noble, but whose weak point 
it was always to complain to everybody about money 
matters, no doubt acknowledged having been too hasty. 
When he returned to Prague in August, Tycho brought 
him to the Emperor, who congratulated him on his recovery, 
and promised him the ofBce of Imperial mathematician on 
condition that he should work jointly with Tycho on the 
new planetary tables, which Tycho begged the Emperor's 
permission to call the Eudolphean or Eudolphine tables.' 

It was mentioned above that Tengnagel was engaged to 
be married to Tycho Brahe's second daughter, Elisabeth. 
On the 5 th April 1601, Tycho wrote a letter (in Danish) to 
his friend Holger Eosenkrands, inviting him to the wedding, 
which was to take place between^ Easter and Whitsuntide, 
and the following day he wrote another letter (in Latin), in 

' This name occurs here for the first time. Perhaps he had come to Tycho 
on the 15th August 1596, as we read in the diary : " Rediit Tycho Hafuia, cum 
eo duo studiosi, alter Germanus commendatus a Landtgravio, alter Danus, 
Joannes nomine." 

2 Opera, viii. p. 741. ' Gassendi, p. 177. 



wliicli lie mentioned that Le expected liis sister Sophia.^ 
Neitlier she nor Eosenkrands came, however, to the wedding, 
%Yhich was celebrated on the 17th June, after which the 
married couple set out for Westphalia, the home of the 
bridegroom, accompanied by Eriksen.'' 

Tengnagel does not seem to have occupied himself much 
with astronomy, and probably did not take an active part in 
the scientific work in Tycho's house. At Prague, Tycho 
had not as many assistants as at Hveen. In addition to 
Longomontanus, Miiller, and Eriksen, he was assisted for 
some time by Melcliior Joestelius, Professor of Mathematics 
at Wittenberg ; ° by Ambrosius Rhodius, who left Prague 
shortly before Tycho's death, and likewise became Professor 
at Wittenberg ; by a certain Matthias Seiffart, who after- 
wards fur some years assisted Kepler in computing and 
observing ; and from June 1 60 1 by a young Dane, Poul 
Jensen Oolding.* It appears also that Simon Marius 
(Mayer), who afterwards obtained some notoriety by laying 
claim to various discoveries and inventions long after they 
had been published by others, spent some time at Prague 
with Tycho and Kepler in the summer of 160 1.'' The 
Imperial physician, Hagecius, with whom Tycho had corre- 
sponded for so many years, died on the i st September 1 600, 

' The Danish letter is printed in Danske Magazin, ii. p. 360 (translated in 
Weistritz, ii. p. 366) ; the Latin one is only alluded to ibid, and iii. p. 23. 

2 Epist. cd. jffanschius, p. 1 79, and Opera, viii. p. 741. 

' Joestelius must have returned to Wittenberg before June 1600, when he 
observed the solar eclipse there (Kepler, i. p. 56). 

* Son of a wealthy citizen at Kolding, in Jutland; born 1581, died 1640 as 
a clergyman in Seeland. Came to Tycho in June 1600, and was with him till 
his death ; wrote an elegy on him, which is printed by Gassendi, p. 241. 
About him see Norsk Bistorisk Tidshrift, ii. p. 338 (1872). 

■■ On the 27th May 1601 Eriksen wrote to Kepler that Marggravii Anspach- 
ensis Mathematicus, Simon Marius, was expected in a day or two, and would, 
the writer hoped, relieve him of some of the observing (Epist. ed. Ilanschius, 
p. 176), but I cannot find any evidence that Mayer really came. He had 
already in 1 596 published a small pamphlet of the ordinary type on the cumet 
of that year. 


after a prolonged illness, but Tycho found other scientific 
friends at Prague, among whom were Martin Bachazek, 
Eector of the University, Peter Wok Ursinus of Eosenberg, 
Baron Johan von Hasenburg (who was an ardent alchemist), 
and the Jewish chronologist, David Ganz. 

As Tycho at Benatky or at Prague had never more than 
a few assistants at a time, and most of his instruments did 
not reach him till October or November 1 600, the observa- 
tions made in Bohemia cannot compare in fulness and extent 
with those made during an equal period of time at Hveen, to 
which disparity the interruptions caused by Tycho's various 
removals also contributed. In December 1600, and the 
first week of January 1 601, observations were made in the 
Emperor Ferdinand's villa, and on the 3rd March the work 
was resumed in Curtius' house, where Tycho had just become 
settled. Kepler hardly took an active part in the observa- 
tions, but he began preparing for the great work to which 
he afterwards devoted his life. When he arrived at Benatky 
in February 1600, Mars had just been in opposition to the 
sun, and a table of the oppositions observed since i 580 had 
been prepared, and a theory worked out which represented 
the motion in longitude very well, the remaining errors 
being only about 1' } On this a table of the mean motion 
of Mars and the mean motions of the apogee and node for 
400 years had been founded (as was done for the sun and 
moon in the Progymnasmatd). But the latitudes and 
annual parallax at opposition (or the difference between the 
heliocentric and geocentric longitude) gave trouble, and 
Longomontanus was just then occupied with this matter." 

' Kepler, De Stella Mortis, cap. viii. ; Opera, iii. p. 210. Apelt {Reformation 
der Stei'nkunde, p. 276), quoting Gassendi, believes his " duo ininuta " to be a 
misprint for "duodecim;" but Kepler distinctly sajs "intra duorum scrupu- 
lorum propinquitatein. " 

^ The greatest drawback of the Tychonio system was the difficulty of dis- 
tinguishing between the real and apparent orbit of a planet; the greatest 


Kep'er tLerefore began to consider whether the theorv 
migLt ret afrer a"J be Trrong, though it represented the 
longitudes so well : br.t dniing' the short time he was at 
Be::iatlt7 he was enable to make any prosrress in this 
problem, wbicb it eTentnallv took Lim foar years to 

Dnring Kepler's residence with Tycho at Prague between 
October 1600 and April 1601, he seems to tave been 
mainly occupied with a piece of wcrk which cannot have 
been ccngenial to hi™ — a refutation of the book of Eey- 
n:ers Bar. Shortly aiter his arrival in Echemia, Tvcho 
hegan to take legal proceedings for libel against this pereon, 
who had fled to Silesia, from whence he, however, secretlv 
came back some time afterwards.^ In the summer of 1600 
Tycho learned that there was perieulum in mora, as Eeymers 
was very ill ; but even this did not soften Tycho's heart, and 
he p-erslsted in having the poor wretch punished, and per- 
stiaded the EiEper:r to appoint a commission of four members, 
two barons and two Doctors of Law. to try the libeller. But 
just as the trial was ahcnt to commence, Eeymers died, on the 
I jth Angtist 1600. The Em j)eror directed the Archbishop 
of Prague to have every obtainable copy of the book confis- 
cate i and bnmed, while Tycho, who was rather unduly 
pro:id of his system of the world, wished to publish a book 
which was to contain aU the documents on the snbject of 
the alleged plagiarism, as well as a scientific refutation of 
Eeymers' b-Xik. The preparation of the latter tad to be 
undertaken by Kepler, who. whiie battling with intermittent 
fever in 1601, wrote his Aj::Jogia Tyehonis contra Ur-ium, 
in which he showed that neither ApoLonins of Peiga nor 

oteerved Ian— i= at opprsijioa was natmally asFtmied to be the mclinatian <A 
tjie orbit, and tiis tnrD^i ont to hare a different Ta^ae at din=x^Dt Umes, a£ if 
the Ptcdemein cteillatioiis of the crbit reaBy existed. 

- Eepler rr :ie i:. him at Prague in Jannaiy 1600, with': ut reTealing his 
own r.arne [C^pera, L p. -37". 


any one else before Tycho had proposed the Tychonic system. 
Tycho's death made this memoir superfluous, and Kepler 
laid it aside, so that it has only recently been published 
in the complete edition of his works.-"- The same was the 
case -with an unfinished reply to the attack of Oraig on 
Tycho's book on the comet of 1577.^ 

In 1 60 1 Kepler also occupied himself with the theories 
of Mercury, Venus, and Mars, and noticed that it was not 
possible to represent the apparent motion of the planets by 
assuming for the orbit of the sun (or the earth) a simple 
excentric circle with uniform motion, as had always hitherto 
been done, but that it would be necessary to have recourse 
■to an equant as in the planetary theories of Ptolemy. When 
Kepler asked Tycho if he would not mention this in the 
Progymnasmata, he declined to do so, as it would take time 
to investigate the equal motion, and he wanted the book 
published at once. The subject was therefore merely alluded 
to by Kepler in the Appendix with which he wound up the 
book after Tycho's death.^ 

While Kepler was thus reconnoitring the ground for his 
future work on the planets, Longomontanus had before his 
departure finished the lunar theory and tables, the incom- 
plete state of which had so long delayed the publication of 
the Progymnasmata. It is much to be regretted that the 

1 Opera, i. pp. 236-276. It is curious that Gassendi should have fallen 
into the same error with regard to Apollonius ( Vita Coperniei, p. 297). Kepler 
had already, in March 1600, at Benatky, written a short refutation, which is 
printed i. p. 2S1 et scq. 

^ Opera, i. pp. 279-281. 

' In a letter to Longomontanus, Kepler wrote in 1605 : — " Ab Octobri i5oo 
in Augustum 1601 quartana me tenuit. Interim Bcripsi contra -Ursum jubente 
Tychone, & alia ipsius studia pro ipsius arbitrio & meis viribus adjuvi. 
Speculatus sum, indignante Tychone, in Venere, Merourio, Luna, in illis 
utiliter, in Luna plane frustra : Speculatus sum et in Marte, correxi inasquali- 
tatemprimara, . . . ASeptembri, inquam, coepilaboriosissimeinquirereexcen- 
tricitatem solis, in quo labore Tycho mortuus est." Epist. ed. Ranschius,p. 171. 
About the solar excentricity, see below. Chapter xii. 



account of Tycho's lunar theory is very short, and gives no 
account of the supcessive steps which led Tycho to his great 
discoveries in this branch of astronomy. When he wrote 
the report on his labours at Hveen for his Mechanica, he was 
already in possession of the discovery of the third inequality 
in longitude (variation), and of the periodical change of the 
inclination and of the motion of the node. During his stay 
at Wittenberg (if not before) he had from observations of 
eclipses perceived the necessity of introducing an equation 
in longitude with a period of a year, but the theory had 
already required so many circles and epicycles that Longo- 
montanus thought it simplest to allow for this equation by 
using a different equation of time for the moon ; and when 
Tycho did not appear very delighted with this makeshift, 
the pupil answered his master somewhat rudely, that he 
might try to find another method himself, which would agree 
better with the observations.' 

It must have been a great satisfaction to Tycho to see his 
researches on the moon reach at least a temporary conclu- 
sion, as his mind had of late years been so full of anxiety for 
the future that he could doubly enjoy a ray of sunshine. 
The Emperor appears always to have been most friendly to 
him, and Tycho wrote in March 1600 to his sister Sophia 
that Eudolph had not only been very kind to him while 
the plague was raging during the previous winter, and had 
ofEered to send him and his family to Vienna while it lasted, 
but that the Emperor also took the greatest interest in his 

' " Tu ergo ipse aliud inveni, quod cum tuis oonsentiat observatis " (see a 
letter from Kepler to Odontius on Tycho's lunar theory, Opera, viii. p. 627). 
That Longomontanus had enjoyed the advice of Kepler on many points in the 
lunar theory appears from the letters exchanged between them in 1604 and 
1605, in one of which Longomontanus counts up the various steps in the 
work, while Kepler after each item put a mark, and wrote in the margin, 
' ' Vide etiam atqve etiam, hjeo me svadente et prseeunte exemplo. " £ptst. ed. 
JffanscJdus, p. 165. We shall consider the lunar theory in more detail in 
Chapter xii. 


work, bad read the unfinished Progymnasmata, and had con- 
sented to let it Tbe dedicated to him/ But however pleasant 
his relations with the Emperor were, Tycho had often prac- 
tical experience of the scarcity of money in Bohemia, and he 
could not be blind to the shaky condition of the Imperial 
Government, caused by the religious and political ilames 
which, though as yet only smouldering, were certain ere long 
to burst out in their fury, and for the quenching of which 
the weakness of the Emperor did not promise well. Perhaps 
he may sometimes have wondered in his own mind whether 
it might not have been wiser to have remained in peaceful 
Denmark, even without an endowment for his observatory, 
instead of coming to the stormy Bohemia, where he had no 
guarantee for the continuance of his salary but the life of his 
patron, just as in the old days at Hveen. His health would 
also seem to have become shaken, if we may judge from 
Kepler's remark that the feebleness of old age was approach- 
ing, since he would hardly have said so of a healthy man 
only fifty-three years of age. 

But the die was cast, and Tycho Brahe could only try to 
make himself as much at home in Bohemia as possible. On 
the 9th February 1 60 1 the Emperor wrote to the Bohemian 
Estates thatTycho Brahe and his sons desired to be naturalised, 
and to have their names entered on the roll of the nobility. 
It is not known whether this matter was considered by the 
Estates, but the name of Brahe does not occur in their pro- 
ceedings, so that Tycho must have died before he could get 
his wish fulfilled.^ In several of his letters Tycho alludes to 
his intention of buying landed property in Bohemia, and in 
order to do so he took steps to get back the money which he 

' Breve og AlctstyTclcer, p. 85. 

2 F. Dvorsky, Novi zpravy Tychonu Brahovi ajeho rodine (New parfcioularg 
about Tycho Brahe and his family), Oasopis Musea Krdlovstvi desjce/io, vol. 
Ivii,, 1883, pp. 60-77. 


tad lent in 1 597 to the Dukes of Mecklenburg. In accord- 
ance with the terms of the bond, he had, about Michaelmas 
1600, through his kinsman Eske Bille, given notice to 
the agent of the Dukes to repay the capital sum of 10,000 
thaler at Easter 1601 ; and for fear of his letter to Bille 
having been lost, he took the further precaution of giving 
notice himself to the " Landrentmeister," Andreas Mayer, 
to pay the money at' Michaelmas 1601, if Bille had not 
already carried out his instructions.-^ He stated expressly 
that he required the money for buying property in Bohemia, 
and wrote to this effect to Duke Ulrich in April 1601, as 
he had been informed that Mayer had stated that he could 
not get the money together so soon. At Easter the money 
was not forthcoming, as Mayer " at the last moment " was 
disappointed about some money which should have been 
paid to him, but Tycho's money was promised for St. John's 
Day. Bille now sent his own servant to Doberan, where 
Duke Ulrich was then staying, to receive the money, but 
he was again disappointed, and Tycho had on the i8th 
July to send off another reminder, to which the Duke 
answered that the money had been ready, but that Bille's 
servant had not called again. Before the 9th August Bille 
had himself arrived at Rostock to receive the money, which 
the Duke on that day ordered to be paid to him " before 
his departure on Tuesday morning." This must have been 
done, as the cancelled bond is still in the archives at 

There appears to be nothing known as to whether Tycho 

^ Breve og ATetstyhTcer, p. 145. It appears from this letter that an aonual 
interest of 6 per cent, was paid on the capital to Tycho's friend, Professor 
Backmeister, in Rostock (in whose house the quarrel with Parsbjerg had begun 
in 1 566 which led to the loss of part of Tycho's nose). 

^ Liscb, T. Brake u. seine Verh. zu MeMerJmrg, pp. 11, 18. In the letter 
of loth April 1601, Tycho mentions that all his instruments are now con- 
veniently placed in Curtius' house. 


actually purcbased land in Boliemia after receiving back his 
money from Mecklenburg, but it is not likely that be did so, 
as bis life terminated very suddenly soon after. On tbe 1 3tb 
October 1601 (new style) be was invited to supper at tbe 
bouse of tbe Baron of Rosenberg/ and went tbere in company 
with tbe Imperial Councillor, Ernfried Minkawitz. During 
supper be was seized witb illness, wbicb was aggravated by bis 
remaining at table. On returning borne, be suffered greatly 
for five days, wben he became somewhat relieved, although 
sleeplessness and fever continued to harass him. He was 
frequently delirious, and at other times refused to keep the 
prescribed diet, but demanded to be given to eat anything 
he fancied. Five more days elapsed in this manner. During 
tbe night before the 24th October he was frequently heard 
to exclaim that he hoped he should not appear to have lived 
in vain (" ne frustra vixisse videar "). "When the morning 
came, tbe delirium had left him, but his strength was ex- 
hausted and he felt the approach of death. His eldest son 
was absent, and his second daughter and her husband also ; ^ 
but he now charged his younger son and tbe pupils to con- 
tinue their studies, and he begged Kepler to finish tbe 
Rudolphine tables as soon as possible, adding tbe hope that 
he would demonstrate their theory according to the Tychonic 
system and not by that of Copernicus.^ Among those pre- 

^ Kepler dedicated his little book De Fundavientis Asti'ologice to " Petro 
Wok Ursine, Domus Rosembergioae Gubernatori. " 

^ The younger Tycho Brahe had in January 1601 started for Italy in com- 
pany with Robert Sherley, ambassador from the Shah of Persia to various 
European courts. Carteggio di Magini, p. 237. 

3 " Ego in sequentibus demonstrationibus omnes tres auctorum formas con- 
jungam. Nam et Tycho, me hoc quandoque suadente id se ultro vel me 
tacente facturum fuisse respondit (fecissetque si supervixisset) et moriens a 
me, quem in Copernici sententia esse sciebat, petiit, uti in sua hypothesi omnia 
demonstrarem." Kepler, De SteUa Martis, cap. vi. ; Opera, iii. p. 193. Gas- 
sendi (p. 179) gives it in these words ; — " Qusso te, mi Joannes, ut quando 
quod tu Soli pellicienti, ego ipsis Planetis ultro affectantibus et quasi adulan- 
tibus tribuo, veils eadem omnia in mea demonstrare hypothesi, quse in Ooper- 
nioana declarare tibi est cordi." 


sent at his bedside was a namesake of Tycho's, Erik Brahe, 
Count Visingsborg, a Swede by birth, but in the service 
of the King of Poland, whom Tycho thanked for all the 
kindness he had shown to him during his illness, asking 
him to carry his last remembrances to his relations in Den- 
mark. Soon afterwards he peacefully drew his last breath, 
amidst the tearful prayers of his family and pupils. He 
had only reached the age of fifty -four years and ten months ; 
a short span of time (as Gassendi remarks) if we look to 
the age which he might have attained, but a lengthy one ii 
we consider the magnitude of his works, which will live in 
the recollection of mankind as long as the love of astronomy 
remains among us.^ 

On the 4th November the body of the renowned astrono- 
mer was with great pomp brought to its last resting-place 
in the Teynkirche (Tynskykostel), in which a semi- Protestant 
(utraquistic) service was still tolerated. The funeral proces- 
sion was headed by persons carrying candles embellished 
with the arms of the Brahe family ; next was carried a 
banner of black damask with the arms and name of the 
deceased embroidered in gold ; then came his favourite horse, 
succeeded by another banner and a second horse, after which 
came persons bearing a helmet with feathers in the colours 
of his family, a pair of gilt spurs, and a shield with the 
Brahe coat of arms. Then followed the coffin, covered with 
a velvet cloth, and carried by twelve Imperial gentlemen- 
at-arms. Next after the coffin came the younger son or 
the deceased, walking between Count Erik Brahe and the 
Imperial Councillor, Ernfried Minkawitz, and followed by 
councillors and nobles, and Tycho's pupils. Then came the 

^ Kepler wrote in the observing ledger a short account of Tycho's last 
illness, which was printed by Snellius in his Observationes Sassiacm, Lug- 
duni Bat., 1618, pp. 83-84, and in this volume. Note D. Kepler also wrote 
an elegy over Tycho Brahe, which is printed by Gassendi, p. 235 et seq. , and 
in Kepler's Opera, viii. p. 138 et seq. 



widow, walking between two aged gentlemen of liigh rank, 
followed by^her three daughters similarly attended. A long 
funeral oration was delivered by Dr. Jessinsky of Witten- 
berg, with whom Tycho Brahe had lived for some months 
two years before. He praised him for having led a life 
befitting a Christian and a learned man, living happily with 
his wife and family, keeping his sons to their studies, and | 
his daughters to spinning and sewing, for being civil to 
strangers, charitable to the poor. He was open and honest ' 
in his dealings, was never hypocritical, but always spoke his 
mind, by which he sometimes made enemies. The speaker 
also dwelt on his scientific merits, and the favour shown to 
him ■ by many princes ; and it is characteristic of the time 
that a reference to his deformed nose and the plagiarism 
and calumnies of Eeymers, as well as a detailed account of 
his last illness, were included in the oration.'^ The tomb is i 
at the first pillar on the left side in the nave, next the\ 
chancel, where Tycho's children some years later erected • 
over it a handsome monument of red marble, which still 
marks the spot. It consists of a tablet standing upright 
against the pillar, with a full figure in relief of Tycho 
Brahe clad in armour, with the left hand on his sword-hilt 
and the right on a globe, underneath which is a shield 
with the arms of Brahe, Bille, and the families of his two 
grandmothers, Ulfstand and Rud. The helmet stands at 
his feet. Bound the tablet runs an inscription recording the 

1 " De vita et morte D. Tychonis Brahe Oratio FunebrU D. Johannis Jessenii, 
Pragae, 1601, 4to, Hamburgi, 1610, and reprinted by Gassendi, pp. 224-235. 
In May 1602 the Kinfc of Denmark wrote to the Elector of Saxony to com- ' 
plain of the unfair way in which Jessenius had alluded to the broken noae 
(" facies decora et aperta, quam ante annos triginta Rostochii quidam noctu 
ausu prorsus sicario Isesit, vestigio ad mortem usque semper conspicuo "). The 
duel, he added, had been a fair fight, and the two adversaries had always 
afterw.irds been good friends, and though Parsbjerg's name had not been 
mentioned, the story was so well known, that the remarks of the orator were 
most insulting, and ought publicly to be retracted. Danske Magazin, ^ih. 
Series, ii. p. 325. 


name and date of the death of the deceased.^ Ahove is a 
smaller tablet with his motto, &se potius quam haberi,^ and 
a lengthy Latin inscription recording his life and merits, 
and mentioning that his wife is also buried here ; while at 
the foot stands an inscription from Stjerneborg, " Non fasces 
nee opes, sola artis sceptra perennant." ^ 

It is scarcely worth mentioning that a silly rumour very 
soon began to spread that Tycho Brahe had died from 
poison, administered by some envious courtier at Prague, 
or, as others thought, by his old enemy Eeymers Bar. As 
the latter died fourteen months before his supposed victim, 
it would indeed have been a remarkably slow poison.* 

The most important inheritance which Tycho left to 
Kepler and to posterity was the vast mass of observations, 
of which Kepler justly said that they deserved to be kept 
among the royal treasures, as the reform of astronomy could 
not be accomplished without them. He even added that 
there was no hope of any one ever making more accurate 
observations, for it was a most tedious and lengthy business ! 
This would have been perfectly true if the telescope had not 
afterwards been invented. It is not here the place to set forth 
how Kepler, when Tengnagel had given up pretending that 
he was going to work out the theory of the planets, took up the 
work, and how his mighty genius mastered it and gave to the 
world the great laws of Kepler, at one breath blowing away 
the epicycles and other musty appendages which disfigured 

1 Anno Domini MDCI die 24 Octobris obiit illustris et generosus Dnus 
Tycho Brahe, Dnus in Knudstrup et Prjeses Uraniburgi, & Saorse Csesareie 
Maiestatis Consiliarius, cujus ossa hie requiescunt. 

^ Sometimes he wrote it "Non haberi sed esse." 

' The inscription is printed in DansTce Magazin, ii. p. 357 ; Weistritz, ii. 
p. 362, where the tombstone is also figured. 

* Andreas Foss, Bishop of Bergen, who had visited Tycho in 1596, wrote 
to Longomontanus in February 1602 to inquire if the rumour had any founda- 
tion (Bang's Samlmger, ii. p. 529 ; Weistritz, i. p. 195). The astrologer Rol- 
lenhageu wrote at the same time to Kepler that Tycho evidently died "per 
Ursianum quoddam venenum" [Epist. £epler{, ed. Sanschius, p. 193). 


tlie Copernican system. But Kepler was not only a great 
genius, lie was also a pure and noble character, and lie 
never forgot in his writings to do honour to the man 
without whose labours he never could have found out the 
secrets of the planetary motions. On the title-page of his 
Astronomia nova de motibus stellce Martis, he states that 
it is founded on Tycho's observations, and on that of the 
TabulcB Rudolphince he mentions Tycho as a phoenix among 
astronomers.-"^ And it was no exaggeration. Archimedes 
of old had said, " Give me a place to stand on, and I shall 
move the world." Tycho Brahe had given Kepler the 
place to stand on, and Kepler did move the world ! And 
so it was with Kepler's labours in other fields, as we may 
see in that wonderfully interesting book, Ad Vitellionem 
Paralipomena, sive Astronomice Pars Optica, where Tycho's 
name is quoted so constantly as having supplied the materials. 
Kepler and Tycho had squabbled often enough while the 
latter was alive, but after his death this was forgotten, and 
Kepler's mind had only room for gratitude for having 
become heir to the great treasures left by Tycho. But on 
the other hand, it must be conceded that it was fortunate for 
Tycho's glory that his observations fell into the hands of 
Kepler. Longomontanus would doubtless have hoarded them 

' "Tabulae Rudolphinse, qiiibus astrononiioae scientiae, temporum longin- 
quitate collapsse, restauratio continetur, a Phoenice illo Astronomorura 
TVGHONE ex illustri et generosa Eraheorum in Regno Daniae familia 
oriundo equite, primum aniino concepta et destinata anno Christi mdlxiv., 
exinde observationibus siderum accuratissimis, post annum praecipue MDLXXII., 
quo sidus in Cassiopeiae constellatione novum effulsit, serio affectata, variisque 
operibus, cum mechanicis, turn librariis, impenso patrimonio amplissimo, 
accedentibus etiam subsidiis Friderici II. Danias Regis, regali magnificentia 
dignis, tracta per annoa xxv. potissimum in insula freti Sundici Huenna et 
arce Uraniburgo, in hos usus a fundanientis exstructa, tandem traducta in 
Germaniam inque aulam et nomen Rudolphi Imp. anno mdiic. Tabulas 
ipsas, jam et nuncupatas et afltectas, sed morte auctoris sui anno MDCI. desertas, 
. . . perfecit, absolvit adque causarum et calculi perennis formulam traduxit 
Johannes Kepplerus." (Ulm, 1627.) 


carefully as a great treasure, but he would most certainly 
not have discovered the laws of planetary motion, and 
Tycho's exile thus turned out to be of vast advantage to 

' Delambre has made this remark in a somewhat exaggerated form, Bist. 
de I'Astr. modeme, ii. p. xiv. : " Si Tycho fut rest^ dans son lie, jamais Kepler 
ne se fut rendu a ses invitations ; nous n'aurions certainement pas la Thiorie 
de Mars, et nous iguorerions peut-etre encore le veritable syst^me du Monde." 




Among the most important instruments in use at Alexandria 
were the so-called spheres or armillEe. These are said to have 
been used in China at an early date,'- but the invention has 
doubtless been made independently by the Greek astronomers. 
They were probably known at the time of Timocharis and 
Aristillus (about 300 B.C.), and it is certain that Hipparchus 
employed them. In the complicated form used by him and his 
successors (called by Tycho " armillse zodiacales ") the instru- 
ment consisted of six circles, of which the largest represented 
the meridian, and was carefully placed in position on a solid 
stand. On the inner rim it was furnished with two pivots, 
representing the north and south poles, on which turned 
a slightly smaller circle, the solstitial colure, to which was 
fixed immovably and at right angles another of the same size, 
representing the ecliptic. The colure was furnished with 
pivots representing the poles of the ecliptic, and on these 
turned two circles, one larger than the colure, another smaller 
than it, while the latter enclosed a sixth circle, which could 
slide inside it, and was furnished with two sights diametrically 
opposite to each other. With this instrument the difference 
of longitude and latitude could be measured, the circles being 
divided to one-sixth degree, while half that quantity could 
be estimated. 

' About the armillse (equatorial) of the Chinese, see Observations matliemati- 
ques, astronomiques, dec. tiries des anciens livres Chinois, red. par Souciet, 
ii. p. 5, iii. p. 105, and my paper on the instruments at Peking in Copernicus, 

vol. i. (1881), p. 134 e( seq. 




The Arabs constructed similar instruments, and already 
Mashallah, wlio lived about the year 775 (before the time of 
Al Mamun), wrote about astrolabes and armillse, and these 
were used by Ibn Tunis, Abul Wefa, and others.^ Alhazen 

Gemma's Astronomical King. 

also made use of armillas for his investigations on refraction, 
and it has even been assumed that he is the inventor of the far 
simpler equatorial armillas, which are generally ascribed to 
Tycho Brahe, who also considers himself as their inventor.^ 
But in any case, it is certain that equatorial armillas were not 
known in Europe ; that Walther, the principal observer be- 
fore Tycho, only knew zodiacal armillee ; and that the principle 
of equatorial ones was first described in 1534 by Gemma 
Frisius, who, however, only designed an instrument of very 

^ S^dillot, ProUgomines des tables astron. d'Oloug-Beg, Paris, 1847, p. xvi. 
Mimoire sur les instruments astron. des Arahes, Paris, 1841, p. 19S. Abal 
^yefa used only five circles, the smaller latitude circle being crossed diamet- 
rically by a pointer or by a tube carrying the sights. 

^ S^dillot, ProUgomirtes, p. cxxxiv. ; Mimoire sur les instr., p. 198 ; but the 
" armille ^quatoriale " mentioned in the latter place is evidently nothing but 
Ptolemy's instrument for observing the solstices, i.e., a graduated circle in the 
plane of the meridian. 


small dimensions, intended to be held in the hand.i Tycho 
remarks that the instruments of the ancients were of solid 
metal, and as they had to be very large to allow spaces of lo' 
to be marked on them, they must have been very cumber- 
some ; ^ and it is deserving of particular notice that he has an 
open eye to the importance of perfect symmetry in the instru- 
ment. He points out that the poles of the ecliptic at different 
times occupy different positions with regard to the meridian, 
and that the instrument therefore must be subject to severe 
strains, which would seriously affect the accuracy of the 
observations, even if the circles are of moderate dimensions 
and not too heavy. For the same reasons he rejected the 
clumsy "Torquetum" of Eegiomontanus, which had never 
been much used.^ 

Although Tycho possessed a zodiacal instrument which had 
the advantage of consisting only of four circles, he chiefly 
made use of equatorial armillse, which instruments represent 
a great step forward, on account of their comparative simplicity 
and perfect symmetry. He constructed three instruments of 
this kind, which are all figured in his Mechanica. The first 
one, which was mounted in the small northern observatory of 
Uraniborg, consisted of three circles of steel, of which the me- 
ridian and the equator were firmly joined together, and both 
the equator and the movable declination circle were furnished 
with sights (made of brass), which could be moved along the 
circles, and to which the observer applied his eye, while a 
small cylinder in the centre of, and perpendicular to, the polar 
axis served as objective sight. The second instrument was 
placed in the small southern observatory, and only differed 

1 Traetatus de annulo astronomico. The author possesses a scarce little 
book in which the various uses of simple circles, quadrants, and systems of 
circles (including Gemma's rings) are described. Annuli astronomici, instru- 
menti cum certissimi turn oommodissimi usus, ex variis autkoribus. Lutetise, 
1557, small 8vo., 159 S. 

2 Progymn., i. p. 140 ; Epist, p. 9. 

^ Mechanica, fol. 0. 4 ; Progymn., i. p. 141. 


from tiie first one by the equator being movable and attached 
to a revolving (but not graduated) declination circle, while 
a smaller and graduated declination circle carried sights. 
The undivided circle might very well have been left out and 
the graduated one fixed to the equator. The outer circle 
(meridian) was nearly five feet in diameter.^ 

The third and most important instrument of this kind was 
mounted in the largest crypt of Stjerneborg and was far 
more extensively used by Tycho, who considered it one of 
his most accurate instruments. It consisted merely of a 
declination circle g|- feet in diameter, and a semicircle, which 
represented the part of the equator below the horizon, and 
rested on eight stone piers. The former has two pointers 
turning round a small cylinder in the centre of the polar 
axis, and perpendicular to the plane of the circle, and each 
furnished with an eye-piece sight, while a third sight slides 
along the equator. The polar axis (of iron, but hollow) could 
be adjusted in inclination and azimuth by screws, which acted 
on a square plate in a hole in which the lower pointed end 
of the axis fitted. By reversing the circle double observations 
of declination might be taken, using first one sight and then 
the other, and Tycho remarks that this instrument had the 
further advantage over the two others that stars near the 
equator were as easily observed as those more distant from it, 
as the equatorial arc was at some distance behind the decli- 
nation circle. 

Circles and semicircles had naturally been in use from a 
very early date. We need only refer to the astrolabium of 
Ptolemy, which consisted of a graduated circle inside which 
another circle could slide, carrying two small cylinders dia- 
metrically opposite to each other, while the instrument was 
kept vertical by a plumb-line. This astrolabium was imitated 
by many successive astronomers ; among others, by Abul Wefa, 

•■ Also figured in Progymn., i. p. 251. 

who has described a meridian circle for observing the sun,^ 


while smaller circles became extensively used, particularly 

' S^dillot, Mimoire, p. 196 ; Wolf's Geschichte der Astronomic, p. 132. 


by navigators. Nonius suggested attaching the pointer or 
alidade to some point on the circumference instead of to the 
centre, as the divisions on this plan might be made twice as 
large as usual.^ I only mention this proposal because Tycho 
(who does not allude to Nonius) constructed a large semi- 
circle revolving round a vertical axis, with a long ruler 
turning on a pivot at one end of the horizontal diameter. 

In addition to complete circles, quadrants were also used 
long before Tycho's time, though not extensively. Ptolemy 
describes a meridian quadrant attached to a cube of stone or 
wood, with a small cylinder in the centre of the arc, of which 
the shadow indicated the altitude of the sun on the gradua- 
tion.^ Among the numerous instruments which Nasir al-din 
Tusi erected in the splendid observatory at Meragha, in the 
north-west of Persia (about a.d. 1260), was a Ptolemean 
mural quadrant, made of hard wood, and with a radius of 
about twelve feet. The limb was of copper, on which three 
arcs were drawn ; the middle one was divided into degrees, 
while of the others, one showed every fifth degree, the other 
the minutes (all of them ?). Nasir al-din mentions the in- 
strument of Ptolemy, which evidently had served him as a 

Tycho Brahe is therefore not (as supposed by some writers) 
the inventor of the mural quadrant, an instrument which up 
to the end of the eighteenth century was the most important 
one in astronomical observatories. Of course he cannot have 
known anything of the Arabian quadrants, but the descrip- 

^ Delambre, Astr. du moyen age^ p. 399. 

^ As remarked by Delambre {Astr. ancienne, ii. p. 75), it appears doubtful 
whether Ptolemy ever actually used an instrument of this kind, as he only 
quotes one observation made with it, the difference between the sun's altitude 
at the two solstices, for which he gives exactly the same value as had been 
found by Eratosthenes ; and as his latitude was 15' wrong, his quadrant (if he 
used it) must have been very small. 

^ Monatliche Qorrespondenz, xxiii. (181 1), p. 346. A perfectly similar 
description from an Arabian MS. by Muvayad al-Oredhi of Damascus is given 
by Sddillot, Mimoire, p. 194. 


tion of Ptolemy must have been familiar to him. The 
advantage of meridian observations for many purposes was 
also well known before bis time, particularly for finding tbe 
declination of tbe sun, wbieb gave its place in tbe zodiac by 
the tables. Hagecius had even observed the altitude and 
time of transit of the new star over the meridian,^ but nobody 
had erected an instrument permanently in the meridian. 
The great superiority as to stability which a mural quadrant 
possessed over the armillEe did not escape Tycho ; and as he 
was the first thoroughly to perceive the influence of refrac- 
tion in altering the apparent positions of stars, the wish 
naturally arose to observe the stars at their greatest altitude 
on the meridian, where that influence was smallest.^ 

From the meridian quadrant to quadrants which could be 
placed in any azimuth the transition was simple enough, and 
we find accordingly among the instruments at Meragah an 
"instrument des quarts de circles mobiles." This consisted 
of an azimuth circle on which were two quadrants turning 
on a common vertical axis, by which two observers could 
find the altitudes and difference of azimuth of two objects.^ 
In Europe an azimuth instrument seems to have been first 
used by Landgrave Wilhelm IV., who observed altitudes and 
azimuths of the new star of 1572, apparently by setting the 
instrument to a certain whole or half degree of azimuth, and 
measuring the altitude when the star reached that azimuth.* 
Quadrants capable of being turned round a vertical axis had 

^ Progym., p. 521. Tycho did not approve of this method, as it involved 
the use of clocks. 

^ For a description of the Tychonic quadrant, see above, p. lOI. 

* Mon. Corresp., xxiii. p. 355. The instrument is doubtless the same as 
described by S^dillot, Mimoire, p. 200. An azimuth circle of copper, 10 cubits 
iu diameter, was in the year 513 after Hedschra erected at Cairo for observa- 
tions of the sun. Caussin, ie livre de la grande Table Halcimite {Notices des 
manuscrits, torn, vii.), Paris, an. xii. p. 21. 

* Progymn., p. 491. At Kremsmiinster observatory there is a small azi- 
muth circle with a vertical semicircle of ivory, dating from 1570. Wolf's 
GescJiichte dcr Astronomie, p. 112. 



been known long before,^ but as it was so much easier to 
graduate a straight line than an arc, the triqnetrum con- 
tinued to be the favourite instrument for measuring altitudes 
down to the end of the sixteenth century. Tycho did not 
think much of this instrument, which he calls " instrumen- 
tum parallacticum sive regularum," and he did not make 
much use of the two he had constructed, and one of which 
was of large dimensions, and furnished with an azimuth 
circle i6 feet in diameter.^ He preferred the " quadrans 
azimuthalis," and constructed four instruments of this kind) 
which were extensively used, though chiefly for merely 
observing altitudes, while the azimuths were rarely taken, 
especially during his later years. The largest quadrant 
(quadrans magnus chaliheios) was enclosed in a square (also 
of steel), of which the side was equal to the radius of the 
quadrant. Two of the sides were graduated, and the alidade 
pointed to these graduations as well as to those on the arc, 
so that the instrument was a combination of a quadrant and 
the " quadratum geometricum " of Purbach (which the Ara- 
bians had also known), which increased the solidity of the 

An important use to which the quadrants were put at 
Uraniborg was the determination of time. At Alexandria 
the beginning, middle, or end of the hour was generally the 
only indication of time which accompanied the observations 
of planets, which was perhaps sufficient, owing to the limited 
accuracy of the observations. The time was found by water- 
or sand-clocks, which were verified by observing the culmi- 
nation of some of the forty-four stars which Hipparchus had 
selected so well that the time could be determined with an 

' The " instrument aux deux piliers " at Mdragah was a modification of 
Ptolemy's quadrant (S^dillot, I. c, fig. 1 13), but it could also be arranged so as 
to be movable in azimuth (see also Monatl. Correap., xxiii. p. 359). 

- Progymn., pp. 142 and 636 ; Epistolw, p. 7$.] 


error not muoli exceeding a minnte.'^ An important step 
forward as regards the accurate determination of time was 
made by the Arabs in the ninth century. Ibn Yunis men- 
tions a solar eclipse observed at Bagdad on the 30th Novem- 
ber 829 by Ahmed Ibn Abdallah, called Habash, who at the 
beginning of the eclipse found the altitude of the sun to be 
7°, while at the end the altitude was 24°. This seems to 
have been the earliest though crude attempt to use observa- 
tions of altitude to indicate time, but the advantage of the 
method was evident, and at the lunar eclipse on the 12th 
August 854 the altitude of Aldebaran was measured equal 
to 45" 30'. Ibn Yunis adds that he from this made out the 
hour-angle to be 44° by means of a planisphere. Ibn Yunis 
communicates a number of other instances from the tenth 
century,^ but the instruments used were very small, and only 
divided into degrees ; and though Al Battani gave formulas 
for the computation of the hour-angle, the Arabians generally 
contented themselves with the approximate graphical deter- 
mination by the so-called astrolabe or planisphere. 

In Europe the use of observations of altitude for determin- 
ing time was introduced in 1457 by Purbach, who, at the 
beginning and end of the lunar eclipse on the 3rd Septem- 
ber, measured the altitude of " penultima ex Plejadibus." ^ 
Bernhard Walther was the first to introduce in observatories 
the use of clocks driven by weights. Thus we find among 
his observations one of the rising of Mercury. At the time 
of rising he attached the weight to a clock of which the 
hour-wheel had fifty-six teeth, and as one hour and thirty- 
five teeth passed before the sun rose, he concluded that the 
interval had been one hour thirty-seven minutes. Walther 

' Schjellerup, Sur le clironomitre cdeste d' Ilipparque {Copernicus, vol. i., 
1881, p. 25). 

^ Oaussin, I. c, p. 100 et acq. About some errors of copying, by which some 
of the observations were affected, see Knobel's paper on Ulugh Beigh's Cata- 
logue, in the Monthly Notices of the Roy. Astr. Soc, xxxix. p. 339. 

' Scripta cl. mathematiei J. Regiomoniani, Norimb., 1544, fol. 36. 


adds that tliis clock was a very good one, and indicated 
correctly the interval between two successive noons ; but all 
the same he must have seen how unreliable it was, for 
though he used the clock during the lunar eclipse in 14S7, 
he at the same time measured some altitudes.^ 

In Tycho Brahe's observatory the clocks never played an 
important part. Though he possessed three or four clocks, 
he does not anywhere describe them in detail, while he in 
several places remarks that he did not depend on them, as 
their rate varied considerably even during short intervals, 
which he attributed to atmospherical changes (although he 
kept them in heated rooms in winter), as well as to imperfec- 
tions in the wheels. At the side of the mural quadrant he 
had placed two clocks, indicating both minutes and seconds, 
in order that one might control the other, and in the 
southern observatory was a large clock {liorologium majus) 
with all the wheels of brass. Whether Biirgi, during 
Tycho's residence at Prague, supplied him with a pendulum 
clock, as stated by a later writer,^ must remain very doubtful, 
but that Tycho did not possess such a clock at Urauiborg 
seems certain, as he would not have neglected to describe so 
important an addition to his stock of instruments. As he 
found the clocks so uncertain, Tycho also tried time-keepers 
similar to the clepsydrae of the ancients, which measured 
time by a quantity of mercury flowing out through a small 
hole in the bottom of a vessel, in which the mercury was 
kept at a constant height, in order that the outflow might 
not vary with the varying weight of the mercury. By 
ascertaining the quantity of mercury which flowed out in 

1 Ibid., fol. 50 ct seq. The mere statement, what degree of the zodiac 
was on the meridian [medium coeli] when an observation was made, was, how- 
ever, still very often the only indication of time given, even by Walther. 
See, for instance, Tycho's first observation at Hveen, above, p. 86 footnote. 

- Joachim Eecher, De nova temporis demetiendi ratiune thcoria (16S0), 
buoted by E. Wolf, Geschichte d. Astr., p. 370. 


twenty-four hours, it was easy to make out the interval 
which passed between the culmination of the sun and a star 
by starting the time-keeper when the former passed the 
meridian, and letting it run until the latter passed, and then 
■weighing the amount which had flowed out. Instead of 
mercury, Tycho also tried lead monoxide powder, and adds 
to his account of these experiments some remarks, about 
Mercury and Saturn (lead), and their astrological relations, 
which naturally suggested themselves to his mind.^ But 
he does not seem to have used these clepsydrse except by 
way of experiment, and his methods of observing made 
him in most cases independent both of them and of the 
clocks. In addition to the altitudes (about which he justly 
remarks that they must not be taken too near the meridian, 
where they vary very slowly, nor near the horizon, where 
they are much affected by refraction), he observed hour- 
angles of the sun or standard stars with the armillse to con- 
trol the indications of his clocks, and his observations ot 
the moon, comets, eclipses, &c., where accurate time deter- 
minations are indispensable, were thereby doubly valuable. 
Occasionally azimuths were also observed for the same pur- 
pose, the zero of the azimuth circle having been found by 
observing: the east and west elongation of the Pole Star.^ 

For observations of altitude Tycho also used a sextant 
of 5 J feet radius, turning on a vertical axis, with one end- 
radius kept horizontal by means of a plumb-line attached to 
the centre of the radius. We have already mentioned that 

1 "Est in Merourio, quicqiiid quEerunt Sapientes . . . Sicque Saturnus 
et Mercurius ooniunctis operibus banc inquisitionem expedirent : cum & 
secundum Astrologos, illorum coniunctio aut benevola invicem radiatio 
. . . aut etiam intuitus beneuolentior, pra3 ceteris aliis significationibus ad 
ingenii et solertise contemplationisque profunditatem, laborisque invictam 
constantiam, plurimum conducere oredantur." Progym., p. 151. 

^ Epist., p. 73. Kothmann was, therefore, not the inventor of this method 
ot finding the meridian, as supposed by Wolf (Geschichte, pp. 374 and 598). 
Tycho had already used the Pole Star for azimuth in 1578, as appears from 
bis MS. journals and Observ. comet,, p. 16. 


Tycho, driven by necessity, had observed altitudes of the new 
star with a sextant, and as the planets never could attain an 
altitude above 60°, he found a sextant a convenient instru- 
ment for many purposes, and specially mentions that it was 
easily taken asunder and transported wherever required. 
Though Tycho believed himself to be the inventor of this 
instrument, he had been anticipated by the Arabs, as A\ 
Chogandi in 992 at Bagdad erected a sextant (which is even 
said to have been of sixty feet radius) for measuring the in- 
clination of the ecliptic.^ 

The sextant was with Tycho Brache a favourite instrument, 
which he had already constructed for Paul Hainzel in 1569 
for measuring the angular distances of stars. At Ilveen he 
constructed three large sextants for this purpose. One of 
these, which was placed in the great northern observatory, 
and was made entirely of brass, was on the same plan as the 
Augsburg instrument, the arc being attached to the end of 
one arm, the two arms being placed at the proper angle 
by a screw, the eye of the observer being at the hinge on 
which the arms turned.^ The second was placed in one of 
the crypts of Stjemeborg, and was a solid sextant of wood, 
covered with painted canvas, and a brass arc 5 J feet radius, 
braced with stays and supported on a globe sheeted with 
copper, which enabled the two observers to place it in the 
plane through the two stars to be measured, while they 
steadied it in the position required by two long rods with 
pointed ends which rested on the floor. One of the observers 
sighted one star through a fixed sight at one end of the arc 

^ I^. A. Siidillot, Mimoire, p, 204 ; Muiiriaux paur servir a Vkitt. del 
sciences chezlcn Green et lei Orknlaux, i. p. 358. I'rMyomiineii (1847), p. "lii. 
Sarafedaula, who founded tho Bagdad obBervatory, was not a Chaliph, as 
Bupposed by Bailly and Wolf, but Emir-ul-umara. 

" fkrlunH eluili/heus, nsc'l already in 1577; Ahc/ianica, foL 70.; He mundi 
ueik. ree. phen., p. 460. The sextant at Cassel (constructed from Wittich's 
descrijjtion; also required one obaorver only, who placed his eye at the centre 
of the arc. 


(C), wliile tlie other observer pointed to the other star through 
a sight at the end of a movable radius. Both observers em- 


ployed the same object-sight, a small cylinder (A) at the centre 
of the arc and perpendicular to the plane of the sextant. As 
the observers when measuring very small distances would 


get tlieir heads too close together, there was for that purpose 
a second cylinder on one of the end-radii (F), and a removable 
sight on the arc (G), placed so that the line through them was 
parallel to a line from the centre to the middle of the arc. 
One observer then sighted along these^ and the other along 
the movable arm as usual.^ 

For measuring small distances (less than 30°) Tycho also 
constructed an "arcus bipartitus," consisting of a rod 5 J feet 
long, with a cross-bar at one end, having at each extremity a 
small cylinder, and two arcs of 30° at the other end, of which 
the cylinders occupied the centres. With this instrument, 
which was placed in the great northern observatory, the dis- 
tances of the principal stars of Cassiopea inter se were mea- 
sured in order to fix the position of the new star by the 
measures taken in 1572-73.^ 

The size of these various instruments, as well as their solid 
construction, would not have been sufiicient to ensure the 
accuracy in the observations which Tycho actually attained, 
and which so much exceeded that reached by previous 
observers, if he had not added special contrivances for that 
purpose. Before Tycho's time there was only one way of 
making small fractions of a degree distinguishable — by 
making the instrument as large as possible. In addition to 
Al Chogandi's 60-foot sextant, a quadrant of 21 feet radius is 
said to have been constructed by Al Sagani (about the year- 
1000), and the value which the Arabs were obliged to attach 
to large instruments was expressed in the remark of Ibn 
Carfa, that if he were able to build a circle which was sup- 
ported on one side by the Pyramids and on the other by the 
Mocattam mountain, he would do it.* 

' Sextans trigonicus. Mech., fol. D. 5 ; Progymn, p. 248. 

2 Arcus bipartitus. Mech., fol. D. 4. 

^ Sddillot, ProUgomines, pp. Ivii. and oxxix. The 180-foot quadrant of 
Ulugh Bey was doubtless a kind of sundial, such as are also found in India. 
Ibn Yunis quotes an observation of the autumnal equinox of 851 at Nisapur 


The first to suggest a method of subdividing an arc ot 
moderate dimensions was Pedro Nunez, whose work, Be, 
Crepioscidis, was published in 1542. He proposed inside 
the graduated arc of a quadrant to draw 44 concentric arcs, 
and divide them respectively into 89, 88, 87 ... 46 equal 
parts, so that the alidade in any position would (more or 
less accurately) touch a division mark on one of the 45 
circles. The indication of this mark was multiplied by 
— ) where n is the number of divisions on the arc on which 

the mark touched by the alidade is. But however ingenious 

this proposal was, it was anything but a 'practical one, as 
it is not easy to divide an arc into 87 or 71 equal parts, 
and the observer would generally be in doubt which division 
was nearest the alidade.-*- Tycho Brahe tried this plan on 
three of the instruments first constructed at Hveen (the 
two smallest quadrants and a sextant), but abandoned it 
again as far inferior to the one he subsequently adopted.^ 
By a strange misunderstanding, the name of Nonius is even 
at the present day often applied to the beautiful and prac- 
tical invention of Vernier (163 1), with which it has nothing 
whatever in common. A step towards the idea of Vernier 
was made by Christopher Clavius and the Vice-Chancellor 
Ourtius, and the latter communicated this plan to Tycho 
in 1590, but it was not much more practical than that of 
Nunez, and was probably never carried out in practice.^ 

"We have seen that Tycho Brahe in his youth followed 
the example of the Arabians by constructing a large quad- 
rant at Augsburg, with a radius of 19 feet. But already 

(Khorassan) with a great armilla which showed single minutes (Caussin, 
p. 148). 

^ The limited accuracy attainable is shown in tabular form by Delambre, 
Moyen Age, p. 404. 

^ Mtchanica, tol. A. 2 ; Epist, p. 62. The quadrans mediocris was, in 
addition to the arcs of Nonius, divided by transversals, and on the sextant 
Tycho removed the Nonian division altogether. 

^ Mechanica, fol. G. 5; compare Chr. Clavii Opera (1612), t. iii. p. 10. 


before that time he had in 1564 obtained a cross-staff 
divided by transversals.^ He says himself that Bartholo- 
mseus Scultetus had got the idea of this method of subdivi- 
sion from his teacher Homilius, and now taught it to him ; 
but in a letter to the Landgrave (of 1587) Tycho states that 
he was seventeen years of age when he at Leipzig learned 
the use of transversals for subdividing a straight line from 
Homilius.^ The latter died, however, in July 1562, when 
Tycho was only 15 J years old, and had only been a few 
months at Leipzig, and it is therefore more probable that 
Scultetus really was the means of imparting the idea to 
Tycho. At all events, Tycho did not attempt to claim 
the invention for himself, though it was afterwards often 
attributed to him. But whether Homilius really was the 
first inventor is more than doubtful, and Scultetus himself 
has even stated that the method was already known to 
Purbach and Regiomontanus.^ We can, however, scarcely 
believe this to have been the case, as it would be diffi- 
cult to explain why the method had never come to light, 
even though Walther notoriously guarded the belongings 
of Eegiomontanus with a curious fear of their being known ; 
and in the Scripta of Eegiomontanus there is no trace of 
his having used so excellent a method. Curiously enough, 
there are two other names mentioned in connection with 
this invention. In his book Alee seu scalce viathematicoe^ 
Digges states that transversals were first applied to the 
divisions on the cross-staff by the English instrument-maker 
Eichard Chanzler, and Eeymers Bar mentions that the 

^ Mechanica, fol. Gr., 2nd page; Progymn., p. 671. 

- Epist., p. 62. 

^ " Voa allerlei Solarien, daa ist, himirjlisohen Cireelu und Uhren . . . duroh 
Bart. Scultetum, Gorlitz, 1572," quoted by K. Wolf, Astr. Mittheilungen, 
xxxiii, p. go. 

■* London, I573i fol' !• 3i where there is a drawing of a rectilinear scale 
with transversals. 



tnethod was described in Puehler's Geometry, pnblislied in 

Under any circumstances, it was Tycho Brache wlio intro- 
duced the use of transversals on the graduated arcs of 
astronomical instruments. He did not use transversal lines, 
such as afterwards became universally used, but rows of dots, 
which were fully as convenient, and he showed that the error 

Transversal Divisions. 

introduced by employing these rectilinear transversals for 
the division of arcs would not exceed 3", which would be im- 
perceptible.^ When Wittich had brought the news of this 
contrivance to Cassel, Biirgi modified it a little by using 
lines instead of the rows of dots, and adding a scale on the 
alidade, the section of which with a transversal line showed 
the number of minutes to be added to the indication of the 
preceding division line, while on Tycho's instruments each 
of the dots corresponded to i'. 

But it was not sufficient to find means to read off the 
measured angle accurately ; it was also of great importance 
to point the instrument to a star with greater precision than 
hitherto, and here Tycho had nobody to show the way. Up 
to his time an alidade had been furnished with two pinnules, 
one at each end, consisting of a brass plate with a small hole 
in the middle, and if this hole was made too small, a faint 

1 Kastner, Oesch. der Math., iii. p. 479; Delambre, AsU: mod., i. p. 299. 

^ De mundi acth. rec. pJten., p. 461 ; Mechanica, fol. I. 2, According to 
E. Wolf [I. c. ), Rothmann has in an unpublished MS. made the same investi- 


star could not be seen, while a larger hole niade the observa- 
tion too uncertain. To meet this difficulty Tycho introduced 
a special pinnule at the eye-end of the alidade, consisting of 
a square plate with a narrow slit close to the side next the 
alidade, while there were three other slits between the three 
other sides and small movable pieces of metal parallel to them. 
By moving these pieces the slits could be made wide or nar- 
row according as faint or bright stars were observed. At the 
object-end was a small square plate exactly of the same size as 
the plate at the eye-end. When the alidade was pointed to a 
star, and the latter through the four slits was seen to touch 
the three sides of the object-pinnule and shine through a slit 
along the side next the alidade, the observer knew that the 
alidade accurately and without any parallax represented the 
straight line between his eye and the star. For observa- 
tions of the sun there was in the centre of the objective 
pinnule a round hole through which the light fell on a small 
circle on the eye-pinnule, and the sunlight was generally 
conducted " through a canal " to keep off extraneous light. 
In many cases, Tycho (as we have already seen) modified 
the arrangement by substituting a small cylinder (per- 
pendicular on the alidade) for the objective pinnule. On 
the armillffi this cylinder was placed in the centre of the 
axis, while the eye-pinnules could slide along the graduated 

Like the transversal divisions, the improved sights were 
introduced at Cassel by Paul Wittich, and the value of 
these improvements was found to be so great, that while 
the observers could formerly scarcely observe within 2', 
the attainable accuracy was now J' or ^'. It appears that 
Wittich had not described the pinnules accurately, as he 
had only given them two slits instead of four, which Eoth- 
mann (or probably Biirgi) soon found preferable. ^ 

^ Epist., pp. 21, 2S-29 ; T. Braliei ct doct. vir. Epist., p. too. 


Before Tycho settled at Hveen he had never regularly 
observed the sun,i but (as we have already mentioned) from 
his birthday, the 14th December 1576, he took regular 
observations of the meridian altitude of the sun, and later, 
when his stock of instruments increased, several quadrants 
were simultaneously employed for this purpose. Above all, 
he employed from March 1582 the great mural quadrant for 
observing the sun on the meridian, while the declination 
was also very frequently measured with the armillse. These 
observations were made with the object of improving the 
theory of the sun's apparent motion. The equinoses of the 
years 1584-88 were carefully determined, but owing to the 
difficulty of fixing the moment of solstice on account of the 
very slow change of declination at maximum and minimum, 
he did not make nse of the solstices to find the position of 
the apogee and the amount of the excentricity of the orbit, 
but determined the time when the sun was 45° from the 
equinoxes, in the centre of the signs of Taurus and Leo. 
Copernicus had followed the same plan, but had made use of 
the signs of Scorpio and Aquarius, while Tycho objected to 
these that the sun was too low in the sky, and the influence 
of refraction and parallax too great. He found the longitude 
of the apogee = 95° 30', with an annual motion of 45" (should 
be 61", Copernicus had only found 24"), and the excentricity 
of the solar orbit = 0.03584, the greatest equation of centre 
being 2° 3;J-'. In the determination of the apogee he was 
more successful than Copernicus ; but while the latter made 
the equation of the centre too small, Tycho made it too great. 
The length of the tropical year he found by combining some 
observations by Walther (reduced anew after determining 
the latitude of Niirnberg) with his own to be equal to 365'' 
5'' 48"^ 45^, only about a second two small. With his new 

' Only in 1574 he had at Heridsvad observed the meridian altitude of the 
sun on seyen days in March and on two days in May. 


numerical data he computed tables for the apparent motion 
of the sun, which he remarks are worthy of considerable con- 
fidence, as they depend on observations made with three or 
four large instruments made of metal, and capable of deter- 
mining the position of the sun within lo", or at most 20"; 
and by comparing the tables with observations by Regiomon- 
tanus, Walther, the Landgrave, and Hainzel, he shows that 
they represent the observed places within a small fraction of 
a minute, while the Alphonsine tables and those of Copernicus 
are often 15' or 20' in error .^ 

The solar observations at Uraniborg led to a result which 
Tycho does not seem to have anticipated. The colatitude, as 
found by the greatest and smallest altitude of the sun at the 
solstices, differed from that deduced from observations of 
the Pole Star by a considerable quantity, which sometimes 
amounted to 4'. Having ascertained that the discrepancy 
did not arise from instrumental errors, he was led to attribute 
it to the effect of refraction. As soon as the great armillEe 
at Stjerneborg were finished, he instituted systematic obser- 
vations to prove this, and to determine the amount of refrac- 
tions at various altitudes. Having first found, by following 
the sun throughout the day with the armillge, that the decli- 
nation apparently varied, as stated by Alhazen in his book on 
optics, he repeatedly in the years 1585 to 1589 devoted a 
whole day, generally in June, when the declination of the 
sun changed very slowly, to investigations on refraction. 
With an altazimuth quadrant he measured at frequent in- 
tervals the altitude and azimuth, and from the latitude of the 
observatory, the azimuth and the declination, he computed 
the altitude, which, deducted from the observed altitude, 
gave the amount of refraction. Another method was by 
observing simultaneously with the quadrant and with the 
armillffi. In the triangle between the pole and the true and 

^ Progym., pp. 1-78. 


apparent places of tlie sun, two sides (real and apparent 
declination) and one angle ( 1 80° minus tlie parallactic angle) 
were known, from wtich the third side could be computed, 
which was the effect of refraction in altitude. This is a most 
inconvenient and troublesome method, and must have given 
the computers plenty to do, if the observations were really 
extensively used in this way for the construction of his 
refraction tables. For these investigations he assumed the 
real declination {i.e., corrected for refraction) as equal to the 
declination as observed on the meridian, as he thought the 
refraction at the meridian altitude at summer solstice (S7J°) 
insensible. He assumed, in fact, that refraction disappeared 
already at 45", where it in reality amounts to 58". Unluckily 
Tycho spoiled the refraction table which he constructed from 
his solar observations by assuming, with all previous astrono- 
mers, from Ptolemy down to Copernicus, that the horizontal 
parallax of the sun was equal to 3'. It is remarkably strange 
that Tycho should not have endeavoured to deduce this 
important constant from new observations which ought to 
have shown him that it was for his instruments insensible. 
This was the only astronomical quantity which he borrowed 
from his predecessors, and it was a wrong one.'^ The re- 
fractions, as given by him, must therefore be diminished by 
3' X cosine of altitude, and it is interesting to see that he 
was well aware of the fact that the refractions as found by the 
stars were different from those which he had mixed up with the 
imaginary solar parallax, as he gives a separate table of stellar 
refraction, in which the quantities are smaller than those in 
the solar refraction table by 4' 30" ; so that according to him 
refraction becomes insensible in the case of stars at 20° 
altitude (where it is in reality 2' 37"). Possibly the refraction 
of stars was not as carefully looked into as that of the sun, 

^ Among Tycho's original observations there Is at the beginning of the year 
1581 a table of solar parallax for every degree (beginning with 2' 58" at 1°) 
up to 60°, altitude. Compare Progymn., p. 80. 


thougli the observations " pro refractionibus fixarum in- 
dagandis" are numerous, particularly in the year 1589, and 
are similar to those of the sun.^ 
j Imperfect though Tycho's researches on refraction were, 
1 they represent a great step forward, as he was the first to 
', determine from observations the actual amount of refraction, 
and to correct his results for it. This was among the earlier 
achievements at Uraniborg, and showed the great superiority 
of the new instruments over the earlier ones. Though not 
unknown to the ancients, and theoretically examined to some 
extent by Alhazen and Vitello (whom Tycho quotes, though 
he doubts whether they really carried out the experiments 
mentioned by them, as their armillse could not have been 
large or accurate), the only astronomer who had practically 
noticed the effect of refraction was Walther. He found, by 
observing the sun when setting, by means of his zodiacal 
•armillse, that the sun seemed to be outside the ecliptic, and 
explained this as being caused by refraction ; but he thought 
this could only be appreciable very near the horizon, and did 
not attempt to investigate its laws, for which his instruments 
would hardly have been accurate enough. 

As to the cause of refraction, Tycho did not think that the 
difference of density of the ether and the atmosphere was of 
much importance, as he points out that in that case refraction 
should not disappear except at the zenith, while he imagined 
it to become insensible half-way towards the zenith. He 
therefore ascribed refraction chiefly to atmospheric vapours, 
though he believed that the atmosphere gradually decreased 
in density and was essentially different from the ether, and 
he naturally rejected as absurd the Aristotelean idea of a 

^ Table of solar refraction, Progymn., p. 79- Por comparison with modern 
refractions (after deducting Tycho's parallax) see Delambre, Astr. mod., i. p. 
1 56. The table of stellar refraction in Progymn., p. 280. On p. 1 24 Tycho gives 
a table of lunar refraction, not differing much from the solar one. In Barretti 
Jlist. Coll., p. 221, there is a table of refraction in A. R. and Decl. for the star 
Spica Virginis. 


sphere of fire encircling tlie earth. He had in his correspon- 
dence with Eothmann several times discussed questions con- 
nected with refraction, not only because the observer at Cassel 
only made the quantity of refraction about half as great as 
Tycho did, but also because Eothmann thought that there 
was no difference between the celestial ether and the air 
except density.^ 

Tycho recognised as an effect of neglected refraction various 
discrepancies between the elements of the solar orbit deter- 
mined by Copernicus and his own results. We have already 
mentioned ^ that he sent one of his pupils to Frauenburg, 

■ and found that the latitude had been assumed 2|' too small, 
which, together with the neglect of refraction, accounted for 
the errors in Copernicus' determination of the obliquity and 
the other elements of the solar orbit, as the longitude con- 
cluded from the eri'oneous declinations would be as much as 
13' in error at 45° from the equinox. 

^^:^ Among Tycho's " puerile and juvenile " observations there 
are very few indeed of the moon ; only now and then the 
approach of the moon to some bright star is mentioned, and 
the distance measured with the " radius " or sextant. At 
Hveen he gradually came to devote more attention to the 
moon, and from 1582 his lunar observations are very regular, 
and become year by year more numerous. They include dis- 
tances from fixed stars, altitudes, declinations, and differences 
of right ascension from fixed stars, and as often as prac- 
ticable the moon was observed in the nonagesimal or that 
point of her daily course in which the effect of parallax took 
place only in latitude. Eclipses were carefully attended to 
whenever they occurred;* but, unlike the ancient astrono- 
mers, Tycho did not confine himself to observing the moon 

^ Progymn., p. 91 ; EpUt, pp. 83, 91, 106. Compare above, p. 206. 
" See above, p. 123. 

' The materials at Tycho's disposal included observations of twenty-one 
lunar and nine solar eclipses. 



at the syzygies and quadratures, but followed lier througtout 
her monthly course year after year, determining her position 
both on and off the meridian, and not forgetting to observe 
her at apogee, or, as he called it, " in maxima remotione 
utriusque epicycli." He thus succeeded in detecting the third 
, inequality in the motion in longitude, the variation, which 
reaches its maximum of 39'. 5 (Tycho found 40'. 5) in the 
octants, when the difference of longitude of sun and moon is 
45°, 135°, &c. But apart from this, he could not be satisfied 
with the way in which Ptolemy had represented the motion 
in longitude (by a deferent and one epicycle, the centre of 
the former moving in a circle round the earth in a retrograde 
direction), because it represented the apparent diameters of 
the moon very badly. In fact, the moon ought, according to 
the theory of Ptolemy, to appear nearly twice as great at 
perigee as at apogee. This had not escaped Copernicus, who 
avoided it by making the deferent concentric with the earth, 
and adding a second epicycle with a motion twice as rapid 
as the first one.^ Tycho chose another way of representing 
the motion in longitude. The deferent (radius =' i) accord- 
ing to him had its centre in a circle with radius 0.02 174, in 
the circumference of which the earth was placed, so that the 
centre of the deferent was in the earth in the syzygies, and 
farthest from it at the quadratures. There were two epi- 
cycles with radii 0.058 and 0.029, ^^^ period in the former 
being the anomalistic month, and the moon moving in the 
latter twice as rapidly and in the opposite direction, in such 
a manner that at apogee the moon was 0.029 outside the 
deferent, at perigee 0.058 -|- 0.029 = 0.087 inside it. The 
effect of the two epicycles gave the maximum of the first 
inequality 4° 59' 30", while the circle through the earth gave 

' For further details of Ptolemy's lunar theory, see, in particular, P. Kempf, 
Vntersuchung ilber die Ptolemdische Theorie der Mundbewegung, Inaugural 
Dissertation, Berlin, 1878. Godfray's Lunar Theory (chap, viii.) gives short 
sketches of Ptolemy's and Copernicus' theories. 


an equation of i° 14' 45" (evection), not differing mucli from 
Ptolemy's values, thougli somewhat more accurate.^ 

So far TycHo had not made much advance, but the dis- 
covery of the third and fourth inequalities was a very 
great step in advance. He probably thought that there were 
epicycles enough in his theory, and therefore he did not 
attempt to account for the variation by adding another. He 
merely let the centre of the first epicycle oscillate (lihraie) 
backwards and forwards on the deferent to the extent of 40'. 5 
on each side of its mean position, the latter moving along 
the deferent with the moon's mean motion in anomaly, and 
the centre of the epicycle being in its mean position at the 
syzygies and quadratures, and farthest from it at the octants, 
the period of a complete libration being half a synodical 
revolution.^ At the same time Tycho's observations showed 

' We have mentioned (p. 272) that Tycho had got part of the appendix on 
the lunar theory printed at Hamburg, but did not make use of the sheets thus 
printed, giving as reason that the printer had done his work badly. Tengnagel 
had given a copy to Magini, who in 1600 pointed out some discrepancies, the 
two first inequalities being stated to amount at most to 7° 41' 15", while the 
dimensions of the circles, so far as Magini could make out, gave 11' or 14' less. 
Tyoho replied that the whole had been recast, partly at Wittenberg, partly in 
Bohemia, and that new tables had been calculated {Oarteggio, pp. 232 and 
238). In his A stronomia Danica, 2nd edit., Amstel., 1640, p. 242, Longomon- 
tanus talks of the lunar hypothesis described above as one " quam anno Sal- 
vatoris nostri 1600 apud Nobilissimum et omnium prffistantissimum astrono- 
mum Dn. Tychonem Brahe invenimus." 

^ I shall not here enter into a discussion of the well-nigh thrashed out 
question whether Abul Wefa's mohadzat is the lunar variation or not, but 
only point out the utter absurdity of the suggestion of L. A. S^dillot 
Matiriaux, i. p. 216) that Tycho might possibly have seen a translation of 
the Alraegist from the Arabian, in which some abstract from Abul Wefa's 
book might have been given. If so, why has nobody else known this book 
until the present century ? Tycho's discovery was not, as S^dillot believed, 
found among his papers and published by Kepler in 1610 ; it is distinctly 
announced in his Mechaniea (fol. G. 2 verso), published in 159S, as a new 
inequality : " Nam & aliam quandara habet ea ina3qualitatis insinuationem 
secundum Longitudinem, quam ab iis animadversum est." Kepler in many 
places mentions Tycho as the discoverer of the variation, and the insinuation 
that Tycho himself did not claim the discovery, but merely called his lunar 
theory "hypothesis redintegrata," is groundless, as Tycho used the same 
expression of his planetary system, which he most assuredly did claim as his 
own {e.g., in a letter to Mastlin, Kepleri Opera, i. p. 45). 


the existence of another inequality, the foui-tli one in longi- 
tude, of which, the solar year was the period, so that the 
observed place was behind the computed one, while the sun 
moved from perigee to apogee, and before it during the other 
six months. We have already mentioned that the solar and 
lunar eclipses continued to be carefully observed by Tycho, 
and at the latest during his stay at Wittenberg, he had 
clearly grasped the peculiarity in the lunar motion just 
described, since Herwart von Hohenburg wrote to Kepler 
(in July 1600) that he had probably heard from Brahe him- 
self how the latter in the paper he had printed at Witten- 
berg ^ had introduced a " circellum annuse variationis, cujus 
initium statuitur sole versante in principio Cancri, ita ut 
in priori semicirculo hujus circelli verus locus Lunae pro- 
moveatur in consequentia, et in posteriori retrotrahatur in 
praecedentia." Kepler also bears witness to the introduc- 
tion of this circellus during Tycho's stay at Wittenberg.^ 
But the representation of the lunar motion had become so 
complicated that Tycho shrank from introducing more circles 
(for which reason he had adopted a mere libratory motion to 
account for the variation), and the idea of a really unequal 
motion was too much opposed to the time-honoured concep- 
tion of uniform circular motion. He (or rather Longomon- 
tanus) therefore ultimately allowed for the annual equation 
by using a separate equation of time for the moon, differing 
by 8m. 13s. multiplied by sine of the solar anomaly from the 
ordinary one, even though this left 5' or 6' of the irregularity 
unaccounted for.^ The correct amount of the equation (il', 

^ "In dem deliquio Lnnse, so sie za Wittenberg drucken lassen" (Kep- 
eri Opera, iii. p. 28). We have seen (p. 272) that Tycho gave up the idea of 
printing the 1-unar theory at Wittenberg. 

^ Kejleri Opera, viii. p. 627. 

' Ibid. In a letter to Archduke Ferdinand, written early in July 1600, 
Kepler gives an account of Tycho's researches on the moon, and alludes to 
the annual equation in the following words (ii. p. 9) ; " Solent ceteri astronomi 
non experientia sed ratione moniti optima tempus aequare propter duas 


and not 4.'.^) was found by Horrox, but lie applied it in the 
same manner as Tycho liad done. 

It is very interesting to see that Kepler had indepen- 
dently discovered the annual equation about the same time as 
Tycho did. In the calendar for 1 598, which he had to prepare 
as provincial mathematician for Styria, Kepler had in detail 
described the solar eclipse of the 7th March (25th Peb- 
raary) 1598, making use of Magini's tables.^ But the phe- 
nomenon turned out very different from what he expected, as 
the eclipse not only was very far from being total (or nearly 
so), but occurred an hour and a half later than expected. 
As the only reservation taken by Kepler had been that the 
eclipse might possibly occur half an hour earlier, he had to 
say something about the cause of this error in the calendar 
for 1599. In this he therefore stated that the solar eclipse, 
as well as the lunar eclipse in February and the Paschal full 
moon, had been more than an hour late ; but the lunar 
eclipse in August had been too early, and it appeared to him 
that one would have to assume " that a natural month or 
period of the moon with regard to the sun in winter, ceteris 
paribus, is a little longer and slower than in summer, and 
the fault is the moon's and not the sun's, as nothing can be 
reformed as to the latter without great confusion ; but whether 
the inequality is to be applied to the moon itself or to the 
length of the day, and what cause it may have in nature and 
the Copernican philosophy, cannot be explained in a few 
words." ^ A letter to Mastlin of December 1598 shows 
that Kepler had not thought further about the matter, and 

causas, primo propter inaequales partium signiferi ascensiones rectas, deinde 
propter motus Solis diurnos inaequales. Hanc posteriorem Tycho negligit, 
causam afferens experientiam, qua deprehendatur in collatione eclipsiuni 
aequalitatis ratiouem iniri non posse, nisi aut haec negligatur aequatio, aut 
annuus circelhis tot epicyclis Lunae insuper adjiciatur." In 1603 Kepler had 
also to explain to Fabricius that experience had shown Tycho the necessity of 
omitting part of the equation of time in the lunar motion (ii. p. 96). 
^ Opera, i. p. 396. ^ Ibid., i. p. 409. 


merely tlirew out this solution because he thought it easier 
to defend than one founded on corrections to the solar theory, 
and he adds that his calendar was not written for learned 
men, and would never be seen outside Styria.^ It happened, 
however, that the calendar was read by Herwart von Hohen- 
burg, who in January 1599 requested Kepler to give him 
further information about the solar eclipse. Being thus 
obliged to consider the matter more fully, Kepler did so in 
his reply, in which his wonderful genius displays itself by 
the way in which he suggests that the moon might be retarded 
in its motion by a force emanating from the sun, which 
would be greatest in winter, when the moon and earth are 
nearer to the sun than they are in the summer.^ At the same 
time he suggests that the phenomenon might also be caused 
by an irregularity in the rotatory velocity of the earth, and 
in after years he accepted this idea, and did not consider the 
phenomenon as caused by an equation in the lunar motion.* 
■ Tycho Brahe's discoveries as regards the lunar motion in 
latitude were as important as those he made of inequalities 
in longitude. The inclination of the lunar orbit to the 
ecliptic had by Hipparchus been found to be 5°, which value 
had been retained even by Copernicus. Several of the 

1 Ibid., pp. 409-41 1. 

^ Ibid., p. 412 et seq. Compare another letter from KepTer to Herwart 
of April 1599, published in Ungedruckte ivissenschaftliche Correspondenz 
zwischen J. Kepler und H. von Eohenburg, 1599. Edirt von C. Anschutz. 
Prag (Altenburg, S. A.), 1886. 

^ This idea is particularly developed in Epitome Astr. Copern., Liber IV. 
{Opera, vi. pp. 359 et seq.). See also an interesting paper by Ansohiitz in Zeit- 
schriftfiir Mathematik und Physik, Jahrgang xxxi. and xxxii., 1886-87. In 
this the author maintains that Tycho Brahe cannot be considered as the dis- 
coverer of the annual equation, because he did not distinctly announce it as a 
separate inequality like the variation, but allowed for the effect of it by leaving 
out part of the equation of time. I confess myself unable to follow this 
reasoning. Tycho clearly perceived the effect of the annual equation, and 
only adopted the peculiar dodge about the equation of time for fear of making 
his theory too complicated. We might as well deny that Columbus discovered 
America because he lived and died in the belief that he had merely come to 
the eastern extremity of Asia. 


Arabian astronomers had, however, noticed that this was not 
correct. Thus Abul Hassan All ben Amadjour early in the 
tenth century stated that he had often measured the greatest 
latitude of the moon, and found results greater than that o£ 
Hipparchus, but varying considerably and irregularly. Ibn 
Tunis, who quotes this, adds that he had himself found 5° 3' 
or 5° 8'. Other Arabians are, however, said to have found 
from 4° 45' to 4° 58', which does not speak well for the 
accuracy of their observations.'- Tycho first began to sus- 
pect that the value of Hipparchus was wrong when examin- 
ing an observation of the comet of T577. On November 13 
he had measured the distance of the comet from the moon, 
and found 18° 30', while the observed distances of the comet 
from stars by computation gave its distance from the moon 
equal to 18° 9', allowing for the lunar parallax. At first he 
attributed the difference to refraction, but in 1587, when the 
moon attained its greatest latitude about Cancer, so that 
neither errors in the parallax nor refraction could influence the 
result much, he found the lunar inclination to be 5° 15', and 
thought it might have increased since the days of Ptolemy, 
just as the obliquity of the ecliptic had diminished.^ The 
examination of all his observations showed him, however, 
later, that the inclination varied between 4° 58' 30" and 5° 
17' 30", while the retrograde motion of the nodes was found 
not to be uniform, so that the true places of the nodes were 
sometimes as much as 1° 46' before or behind the mean ones. 
This inequality of the nodes had not been detected by the 
ancients, because it disappears in the syzygies and quadratures, 
where they alone observed the moon. Tycho explained this 
and the change of inclination by assuming that the true pole 

1 L. A. S^dillot, MaUriaux pour servir, &c., t. i. p. 283 et seq. The sons of 
Musa ben Schaker (about 850) seem to have been the first to find a value 
differing from that of the ancients. Some Chinese observers found 5° 2'. 
Copernicus, an Internal. Journal of Astronomy, vol. ii. (1882), p. 128. 

^ De mundi aeth. rec. phen., p. 40. 


of the lunar orbit described a circle round tbe mean pole with 
a radius of 9' 30", so that the inclination reaches its minimum 
at syzygy and its maximum at quadrature.^ He applied cor- 
rections separately to the latitude for equation of node and 
for change of inclination, a form which was retained even by 
Newton and Euler, until Tobias Mayer showed that the two 
equations can be combined into one, varying with the double 
distance of the moon from the sun, less the argument of 
latitude of the moon.^ 

It would lead us too far if we were in this place to enter 
into a description of Tycho's lunar tables, or of his precepts 
for finding the longitude from his theory.' We shall only 
mention that he was the first to tabulate the reduction, or 
the difference between the moon's motion along its orbit, 
and the same referred to the ecliptic. The table of parallax 
makes this quantity vary between 66' 6" and 56' 21", the 
apparent diameter varying from 32' to 36' at full moon, 
while he believed to have found from his observations of 
eclipses that the diameter appears less at new moon (25' 36" 
to 28' 48"), owing to the limb being "extenuated" by the 
solar rays. He therefore denied the possibility of a total 
solar eclipse, to some extent also misled by the accounts 

^ Copernicus had employed a similar construction to explain the trepidatio 
or (imaginary) oscillation of the equinoxes. 

' In Godfray's Lunar Theory, chap, viii., Tycho's hypothesis is described as if 
he supposed the lunar pole to move in the small circle with double the synodical 
velocity of the node. Though this, of course, is the correct representation of 
the perturbations in latitude, it is not Tycho's idea, as he took no notice what- 
ever of the position of the node with regard to the sun, but let the pole move 
with double the synodical velocity of the moon. In the well-known term 
9'sin((!-2©-t-a), if we, instead of the quantity within the bracket, write 
2 (U - 0) - (S - fl), we get Tycho's period, as the inclination will vary by 
- 9' cos 2 (S - 0). But if we put {« - a ) - 2 (© - jj). the inclination 
will vary by -)- 9' cos 2 (0 - a), and the period is 173 days. That Kepler 
had remarked the importance of the position of the sun with regard to the 
node may be seen from Tab. Rudolph., pp. 89-90 ; Opera, vi. pp. 588 and 648. 
Of modern authors, Montucla seems to be the only one who has remarked that 
Tycho paid no attention to the node {Histoire des Math., i. p. 666). 

^ Por an account of these, see Delambre, Jlist. de VAstr. mod., i. p. 164. 


of the luminosity seen round the sun at the eclipses of 
1560, 1567, and 1598.1 

I'he planets had been favourite objects with Tycho from 
his youth. His very first attempts at observing had been 
sufficient to show him how imperfectly the existing theories 
of the planetary motions agreed with the actually observed 
positions of the planets, and throughout his life he never 
neglected to take regular observations of the five planets.^ 
His early observations of planets were of course similar to 
those made by his predecessors. The ancients had generally 
fixed the position of a planet by mere alignment, or, if the 
distance from a star was small, by expressing it in lunar 
diameters, while conjunctions of planets inter se or near 
approaches to fixed stars were greatly valued as tests of 
theory. As long as Tycho only possessed few and small 
instruments, he naturally often had recourse to these old 
methods, but he commenced also very early to adopt the 
method, first used by Walther, of measuring the distance 
of a planet from two well-known fixed stars.^ At Hveen 
he never quite gave up this method, but he chiefly depended 
on meridian altitudes and observations with the armillee, 
and even the difficult planet Mercury was carefully watched 
for and observed on every opportunity.* 

Though Tycho did not live long enough to try his hand 
seriously at the theory of the planetary motions, we have 

^ Progym., p. 134; Kepler, Ad Vitell. Parol., chap. viii. {Opera, ii. p. 309) ; 
Ricoioli, Almag. novum, ii. p. 372. See also Tyoho'a letter to Mastlin in 
1598 {Opera, i. p. 46). About Tyoho's observations o£ the solar and lunar 
diameters, see above, chapter viii. p. 191. 

^ In a letter to Rothmann {Epist., p. 114) Tycho expressed his regret that 
so little attention was paid to the planets at Cassel, since the positions of fixed 
stars were principally of interest by enabling an observer to follow the course 
of the planets. 

' At first the youthful observer generally only measured the distance from 
one star ; but from December 1564 two stars are often, and from 1569 always 

' The earliest observation of Mercury seems to be of April 17, 1574, at 


seen that he was at Benatky occupied with the theory of 
Mars, and succeeded in representing the longitudes well 
(Kepler says within 2'), while the latitudes gave more 
trouble.'^ But already at Uraniborg he had not contented 
himself with a mere accumulation of material, but had drawn 
some conclusions from the comparison of his results with 
the tabular places of the planets. We have seen that Tycho, 
like Ptolemy and Copernicus, assumed the solar orbit to 
be simply an excentric circle with uniform motion. But 
already in 1 591, he might have perceived from the motion 
of Mars that this could not be sufiBcient, as he wrote to the 
Landgrave that " it is evident that there is another in- 
equality, arising from the solar excentricity, which insinuates 
itself into the apparent motion of the planets, and is more 
perceptible in the case of Mars, because his orbit is much 
smaller than those of Jupiter and Saturn." ^ He concluded 
(strangely enough) that his own planetary system alone 
could account for this, and he can therefore not have had a 
clear idea of the cause of the phenomenon. Again, in his 
letter to Kepler of April i, 1598, he mentioned that the 
annual orbit of Mars (according to Copernicus) or the 
epicycle of Ptolemy was not always of the same size with 
regard to the excentric, but varied to the extent of 1° 40'.' 
This eventually led Kepler to the discovery of the elliptic 
orbits, but it showed him already in Tycho's lifetime that 
the solar excentricity was only half as great as hitherto sup- 
posed, and that the remainder of the equation of centre 
would have to be accounted for by a uniforin motion round a 
punctum cequans (that is, as long as only circular orbits were 

^ Above, p. 303. 

2 Epist. Astr., p. 206. Magini had also noticed this apparent inequality in 
Mara ; see above, chap. ix. p. 2 1 3. Tycho also alludes to it in Mechanica, fol. 
G. 3 : " Turn quoque cirouitum ilium annuum, qaem Copernicus per motum 
Terrse in orbe magno, veteres secundum Epioyolos exousarunt, variationi 
cuidam obnoxium esse perspeximus." 

^ Opera, i. p. 44, iii. p. 267 {De Stella Martis, xxii.). 


admissible).^ There was another important matter in which 
Kepler's suggestion was acted upon. Soon after his arrival 
at Benatky, he found that Tycho, like his predecessors, 
referred all the planetary motions to the mean place of 
the sun, while he had himself in his Mysterimn Cosmogra- 
phicuvi referred them to the actual place of the sun. He 
gave the impulse to this being done in the lunar theory by 
Longomontanus, and he mentions in the Appendix to the 
Progymnasmata that the necessity of this step had also 
become evident in the case of Mars. 

With regard to Tycho's observations and researches on 
comets, we need only refer to Chapter VII., where they have 
been examined in sufficient detail. It is not among the 
least of Tycho's scientific merits that lie finally proved 
comets to be celestial bodies. 

That a new catalogue of accurate positions of fixed stars 
was urgently needed had early been felt by Tycho Brahe. 
The Ptolemean catalogue of stars was fourteen hundred years 
old, and was probably little more than a reproduction of 
the still older catalogue of Hipparchus. None of the Arabian 
astronomers had observed fixed stars, but had contented 
themselves with adding the precession to the longitudes 
of Ptolemy; and the only independent catalogue, that of 
Ulugh Beg, was not yet known in Europe. The co-ordi- 
nates of stars given in Ptolemy's catalogue were known at 
Tycho's time through the two Latin editions of the Almegist 
of 1515 and 1528 and the Greek edition of 1538; but to 
the original errors of observation had been added a goodly 
number of errors of copying, so that the discrepancies of the 
various editions inter se were numerous and large. The 

■' Progymn., p. 821. In the Tuhulm Rudolph., p. 57, Kepler says of Tycho : 
" De solis quidem Eccentrico simplici, cum videret, ilium nou tolerari ab 
observationibus planetarum oaeterorum, desciscere ultimis temporlbus oepit, 
eumque parem oaeteris planetis concessit ; quacunque ea res explicanda esset 


observations of tlie new star and of the successive comets 
made Tycho feel the necessity of getting accurate places 
for his stars of comparison, and when his observatory was 
complete, he took up the work of forming a new star cata- 
logue with great energy. 

By Hipparchus the longitudes of stars had been deduced 
from the longitude of the sun by using the moon as inter- 
mediate link, which method is described by Ptolemy, who 
gives a full account of the manipulation of the zodiacal 
armillse. Unfortunately Ptolemy does not say a word 
about the manner in which the standard stars (Eegulus 
and Spica) were connected with the other stars, nor does 
he give any details about the actual observations on which 
the adopted places of the stars were founded. It is, there- 
fore, not known whether every single star was connected 
with a standard star, or whether he perhaps also made use 
of conjunctions of stars with the moon (which had been of 
great value for the deduction of stellar positions for earlier 
epochs for the determination of the constant of precession),^ 
and nothing but a slight sketch of the method was handed 
down to posterity. The Arabs, as already remarked, did 
not observe fixed stars, and here, as in several other branches 
of practical astronomy, Walther was the first to recommence 
work. At the Niirnberg observatory he introduced a very 
important improvement on the method of Hipparchus by 
substituting Venus for the moon, as the small diameter, slow 
motion, and very small parallax made the planet far more 
suitable for the purpose than the moon. Among the observa- 

^ The statement by Copernicus (De Revolut., lib. ii.), that Menelaus used 
lunar conjunctions to determine a number of star-places, arises perhaps from 
a mixing up of two circumstances, viz., the observations by Menelaus of two 
conjunctions in A.D. 98 (recorded by Ptolemy, vii. cap. 3), and the tradition 
mentioned by several authors, according to which Menelaus in the first year 
of Trajan had compiled a star catalogue which Ptolemy had adopted, after 
adding 25' to the longitudes (Schjellerup's Al SAfi, p. 42 ; Albohazzin, quoted 
by Riecius, Delambre, Moyen Age, p. 380). 


tions published in the Scripta of Eegiomontanus, the first 
observation of this kind is from the 6th March 1489, and 
there are several from the following years ; and as the book 
was published in 1 544, Tycho Brahe has known Walther's 
plan, while the further development of it is due to himself.''- 
The method recommended itself to Tycho because it did not 
involve the accurate knowledge of time by clocks or clep- 
sydrae, while he made this objection to the method followed 
by the Landgrave of observing the altitude of stars, together 
with their transits over the meridian or a certain azimuth. 
The meridian method had been used by Tycho to determine 
the places of twelve stars observed with the comet of 1577, 
and for this purpose he made use of a Aquilse as funda- 
mental star, determining its right ascension by observing 
the meridian transits of it and the moon when not too far 
apart. He knew, therefore, by experience how undesirable 
it was to trust to the clocks.^ 

In the spring of 1582 Venus was most favourably 
situated, and from the 26th February it was for about six 
weeks clearly visible in full daylight even before it passed 
the meridian, so that it could be observed at a sufficient 
height above the horizon to make errors in the adopted 
refractions harmless.' With the sextans trigunicus two 
observers measured the distance between Venus and the 
sun, the shadow of the little cylinder at the centre of the 
arc falling on the movable pinnule ; at the same time the 

^ Tyoho does not allude to Walther, but mentions that Cardan had in 1537 
determined the place of a Librae by means of Venus (though apparently with- 
out reference to the sun), which he found absurd. Copernicus and Werner 
had determined the place of a few fixed stars (particularly of Spica) by measur- 
ing the declination, borrowing the latitude from the catalogue of Ptolemy, and 
from these calculating the longitude and right ascension. Progymn., i. p. 146. 

^ De mundi CEth, rec. phen., p. 32. 

' Therefore Tyoho gladly turned from the morose Saturn and the deceitful 
Mercury {i.e., from the use of timekeepers regulated by lead or mercury) to 
the charming Yenus {Progymn., p. 153). 


altitudes of the two celestial bodies were measured, and 
occasionally tteir azimuths, while their declinations were 
observed by the armillae, and their meridian altitudes as often 
as opportunity offered. Afber sunset the same sextant was 
employed to measure the distance of Venus from certain 
conspicuous stars near the zodiac (Aldebaran, Pollux, and 
some others in the same constellations), while, as before, 
altitudes and declinations were also observed. In deducinsr 
the positions of the stars observed, the motion of Venus and 
the sun in the interval between the day and night observa- 
tions was taken into account. By simple trigonometrical 
operations the difference of right ascension between the sun 
and a zodiacal star was computed, and as the right ascen- 
sion of the sun was known from the solar tables, the absolute 
right ascension of the star was thus found from the 
observations, while the declination was directly measured. 
All the stars thus determined were connected by distance 
measures with the star a Arietis, which he preferred to y 
Arietis, which by Copernicus had been adopted as principal 
standard star, as being nearest to the vernal equinox, but 
which Tycho found too faint to be conveniently observed by 
moonlight. Each observation thus gave a value for the right 
ascension of a Arietis. During the following six years 
Tycho repeated these observations as often as an oppor- 
tunity offered, and, in order to eliminate the effect of parallax 
and refraction, he combined the results in groups of two, so 
that one was founded on an observation of Venus while east 
of the sun, the other on an observation of Venus west of the 
sun ; whUe the observations were selected so that Venus and 
the sun as far as possible had the same altitude, declination, 
and distance from the earth in the two cases. From the 
observations of 1582 Tycho selects three single determina- 
tions, and from the years 1582-88 twelve results, each 


being the mean of two results found in the manner just 
described. The fifteen values of the right ascension of a 
Arietis agree wonderfully well inter se, the probable error 
of the mean being only ± 6", but the twenty-four single 
results in the twelve groups show rather considerable dis- 
cordances, the greatest and smallest differing by i6' 30". 
But anyhow the final mean adopted by Tycho is an exceed- 
ingly good one, agreeing well with the best modern 
determinations. He adopts for the end of the year 1585 
26° o' 30", the modern value for the same date being 
26 o 45 .^ 

From the absolute right ascension of a Arietis thus 
determined, and the directly observed declination, Tycho 
determined the co-ordinates of other stars by measuring the 
distance from a Arietis and the declination, after which the 
spherical triangle between the pole and the two stars (in 
which the three sides were known) gave the angle at the 
pole or the difierence of right ascension. Proceeding thus 
from one star to another round the heavens, Tycho deter- 
mined the right ascensions first for four, then for sis, and 
finally for eight principal standard stars ; and as the sums 
of the differences of right ascension in the three cases only 
differ a few seconds from 360°, he imagined that he had 
proved his results to be extremely accurate. It is needless 
to say that the accuracy cannot be so great as Tycho fondly 
hoped, as the errors of observation would be increased by 
neglect of refraction and by his ignorance of the existence 
of aberration and nutation. But it must be conceded that 
Tycho's results were an immense improvement on the posi- 
tions of fixed stars as previously known, as the comparison 
with the best modern star-places for the nine stars reduced 
to the end of 1585 gives the probable error of Tycho's 
standard right ascensions equal to ± 24". i, and that of his 

i For details see Note E. 


standard declinations (after correcting them for refraction) 

It is interesting to see that observations of absolute right 
ascension were made at Cassel about the same time, and 
by the same method, except that Jupiter was at first used 
instead of Venus. As Jupiter could not be observed with 
the sun above the horizon, this iavolved trusting to the rate 
of the clocks for many hours, which perhaps was more 
feasible at Cassel, where Biirgi introduced the use of the 
pendulum for controlling the clocks. In 1587 Venus was, 
however, made use of, the altitude and azimuth of the 
sun, Venus, and Aldebaran being observed in succession. 
The results thus found for the right ascension of the latter 
star agreed well mfer se, fixing it at 63° 10' for the begin- 
ning of 1586,' or more than 6' greater than that found by 
Tycho. This systematic error, with which all the right 
ascensions determined by means of Aldebaran became 
afiected, and which also, with nearly the same amount, 
entered into the longitudes, was discussed in several letters 
between the Landgrave, Rothmann, and Tycho. The Land- 
grave thought s' or 6' a very trifling quantity, not worth 
mentioning, as nobody hitherto had been able to determine 
longitudes with that accuracy.^ Tycho at first suggested 
that the discrepancy might be caused by an error in the solar 
declination, caused by a faulty suspension of the plumb- 
line which marked the zero point on the quadrant at Cassel, 
and to which Rothmann had referred in a former letter.^ 
Afterwards he concluded that the error was caused by all 
the observations being made in the evening, when refraction 

' See Note E. Adopting the star-places given in Woldstedt's paper on 
the comet of 1577, the probable errors in longitude and latitude of the stars 
on p. 32 of He mwndi (gt7i. rec. phen. turn out to be + I'.iS and + i'.25. 

^ Epist. Astron., p. 78. 

'Ibid., p. 45; compare p. 33. Rothmann suggested that perhaps the appre- 
ciable size of Venus might have something to do with it (p. 88). 


would tend to make the longitude of Venus appear greater.^ 
It seems, however, that the real cause was the unlucky solar 
parallax of 3' which Eothmann (like Tycho) had borrowed 
from the ancients, and which would act particularly injuri- 
ously on his results, as his observations were all made in 
winter, and at low altitudes of both the sun and Venus, and 
not combined, like those at Hveen, to eliminate errors as 
much as possible.^ 

On the basis of the nine standard stars and twelve addi- 
tional stars near the zodiac, Tycho Brahe built up his star 
catalogue. Of a star to be determined, the declination was 
measured directly by the armillge or a meridian quadrant, 
and the distance from a known star was measured with a 
sextant. This furnished, as before, a spherical triangle, with 
the three sides known, from which the angle at the pole 
or the difference of right ascension could be computed. 
Generally the star was connected with two known stars, one 
preceding and one following it, which gave two results for 
the right ascension as a control. Tycho communicates 
twelve examples of -this double determination, the results 
always agreeing within a minute.^ For stars in higher 
declinations the additional precaution was taken of connect- 
ing them with three stars, as in the case of the constellation 
of Gassiopea, in which Tycho was specially interested on 
account of the new star, and which he observed in 1578 
and 1583. The other constellations were all observed in 
the years i 5 8 6 to 1591. It is needless to say that the 

' Prorjymn., p. 274. 

^ R. Wolf, Astron. Mitth., xlv. (1878), p. 131. The Hessian star catalogue 
was to contain 1032 stars, but was never finished. In its incomplete state it 
is published in Barretti Historia Calestii, under the year 1593, which the 
editor has erroneously assumed to be the epoch (instead of 1586), probably 
because the longitudes are about 6' too great (as 7 x 50" = 5' 50"). Compare 
riarasteed's Eist. Cml. Brit., vol. iii., Proleg., p. 90, and p. 21 e« seq., where 
Tyoho's and the Landgrave's star-places are given side by side. 

^ Progymn,, p. 224 et seq. 



twenty-one standard stars were not sufficient, but that it 
became necessary to build further on tHe stars determined 
by tiiem. Magnitudes were frequently noted, and in the 
final star catalogue they were entered, occasionally with two 
dots added (:) or one (.), to show that the star was slightly 
brighter or fainter than indicated by the figure. But these 
estimates of magnitude were probably not made with parti- 
cular care, so that it would be risky to draw conclusions 
from a comparison of them with the more systematically 
made observations of relative brightness of Ptolemy, Al 
Sufi, and astronomers of the nineteenth century.-' 

■ In reducing his observations, Tycho adopted 51" as the 
value of the constant of precession, which he deduced from 
a comparison of his own places for Eegulus and Spica with 
those found by Hipparchus, Al Battani, and Copernicus.^ 
Although the places of Spica recorded by Timocharis and 
Ptolemy gave respectively 49 j" and $3^") ^^ ^^^ sense 
enough to attribute this to the crudeness of earlier observa- 
tions, and pointed out that these often erred very greatly 
as to the relative positions of stars which were supposed to 
have been well observed, so that there was no need of 
assuming any irregularity in the precession of the equinoxes 
in order to reconcile discrepancies in the absolute longitudes. 
The origin of this old idea, that the equinoxes did not recede 
with uniform velocity on the ecliptic, but were also subject 
to an oscillating motion, is shrouded in mystery. The name 
of Tabit ben Korra (who lived in the second half of the ninth 
century) is usually associated with this trepidatio, but the idea 
seems to be very old, and is first mentioned by Theon, the 
commentator of Ptolemy, according to whom " some ancient 
astrologers" had found that the stars had an oscillating 

^ Tycho's star catalogue was reprinted by Kepler in the Taiulce Rudolpliince 
(1627), and by Baily in Memoirs R. Astron. Soc, vol. xiii. 
2 Progymn., pp. 253-255. 


motion 8° backwards and forwards in 672 years ; and accord- 
ing to Al Batraki (Alpetragius in the twelftli century), the 
erroneous value of 36" which Ptolemy had found for the 
constant of precession, gave rise to the whole mischief, as his 
successors could not believe that he had found an erroneous 
value. Al Battani was the only Arabian astronomer of note 
who was not an implicit believer in trepidation, but from the 
time of Al Zerkali of Cordova (about 1060) the theory of 
this wholly imaginary phenomenon was developed minutely. 
In the Alphonsine tables the period of the inequality of 
precession was assumed to be 7000 years, though King 
Alphonso personally seems to have believed precession to be 
uniform. From these tables and the Arabian authors the 
theory was spread to Europe, and was further investigated 
by Purbach and Regiomontanus, who assumed with Tabit 
that the apparent equinox moved in a small circle with a 
radius of 4° 1 8' round the mean equinox, whereby the annual 
precession was sometimes accelerated and sometimes retarded. 
In the sixteenth century trepidation was made the subject 
of two treatises by Johannes Werner of Ntirnberg, and 
in the third book of his great work Copernicus has also 
examined it in detail, and showed how annual precession 
had always varied from the time of Timocharis (300 B.C.) 
till his own time. It was a natural consequence of the 
belief in the motion of the equinox on a small circle that 
the obliquity of the ecliptic should also vary irregularly ; and 
though it had been steadily diminishing since the days of 
Eratosthenes, even Copernicus considered such irregularities 
proved by the observations of the ancients and the Arabians. 
The first to see that the obliquity of the ecliptic had always 
diminished at a regular rate since the commencement of 
history seems to have been Fracastoro (1538)) after whom 
the same was asserted by Bgnazio Danti in 1578-^ 

' Prima volume delV Uso e Fabrica dell' Astrolahio e del Planisferio. Tirenze, 


The authority of Tycho Brake was so great, that the 
mere fact of his having ignored the phenomenon of trepida- 
tion was sufficient to lay this spectre, which had haunted 
the precincts of Urania for a thousand years, and possibly 
much longer. Though he had expressed himself somewhat 
guardedly (promising to discuss the matter further in the 
great work which he did not live to write), he had done 
enough by making his contemporaries aware of the vast 
difference between the accuracy of ancient observations and 
that of his own, and trepidation was never again heard of.^ 

It would not convey a correct idea of the accuracy which 
Tycho attained in his observations if we were to compare 
the positions of stars given in his catalogue with those 
resulting from modern observations. It would certainly be 
possible to reconstruct his catalogue from his original 
observations, but as this considerable labour would not 
benefit modern astronomy, for which a recurrence to Tycho 
Brahe's observations would hardly ever be of value except in 
very special cases, it is not likely to be undertaken. We 
are, however, able to form a conception of the accuracy of 
his results in other ways. First, the star of 1572 was, as 
we have seen, connected by distance measures with nine 
stars in Cassiopea. Computing the positions of these from 
modern data, Argelander found the probable error of one 
distance of the new star (with the sextant of 1572) to be 
± i8".2, while the distances between the stars of Cassiopea 
measured with the arcus bipartitus gave ± 4i".o.^ The 
first result seems rather too small, but as we do not possess 
the original individual observations of Nova, we have no 
way of knowing how many such are embodied in the mean 

■^ About the successiTe development of the ideas on trepidation, see 
Delambre, Moijcn Age, passim, particularly pp. 53, 73, 186, 250, 264; Kastner, 
Geseh. d. Math., ii. p. 60; Mitthcilungen des Coppemicus Vereins zu, Thorn, ii. 
(1880), p. 3 et seq. 

^ Astron. Nachrichten, Ixii. p. 273 (1S64). 


results. From the distance measures of the comet of 1577 
Woldstedt found the probable error of one observed distance 
= ± 4'- 2/ but as he mixed the sextant measures with 
those obtained with the cross-staff, which Tycho always 
mentions as an untrustworthy instrument, this large prob- 
able error is not surprising. The most valuable investiga- 
tion which we possess concerning Tycho's instruments is 
the discussion of the observations of the comet of 1585 
by 0. A. F. Peters.^ When this comet appeared, Tycho's 
collection of instruments was complete, and we may assume 
that the observations are typical. Tycho states that his 
indications of time have been corrected by the observed 
hour-angles of stars, and by recomputing these the mean 
correction of + 22^.5 was found, with a probable error of 
+ 37^. This only shows, as Tycho merely gave the time 
in whole minutes, that the great armillse of Stjerneborg 
were well adjusted. But a very much better proof of this 
is furnished by the observations. By the armillae the comet 
was compared in right ascension with certain standard stars, 
while its declination was observed with the same instrument. 
From the total of these observations Peters found that the 
polar axis of the armillas was inclined to the horizon by an 
angle which exceeded the latitude by only 65" ± 33", 
and formed with the meridian an angle of only 36" + 1 3". 
The probable error of one observation of declination was 
± 49", that of one right ascension = 8 i", and consequently 
that of one observed hour-angle = + 57". The error of 
collimation (or parallax, as Tycho called it) was — 30". i, by 
which amount the observed declinations were too large. 
The comet was also observed with the sextans trigonicus, 
and the probable error of one observed distance was found 

* F. Woldstedt, De yradu praecisionis posUionum cometce 1577. Hel- 
singfors, 1844. 

2 Astron. Nachr., xxix. p. 209 et sc<i. (1849). 


equal to ± 45", the collimation error being— 11 4". 6} 
These results are sufficient to show that Tycho's instruments 
were really made with the great care which he declares he 
had always bestowed on them,* and in connection with the 
above results as to Tycho's standard stars, they exhibit the 
vast stride forward which observing astronomy made at 
Uraniborg, and which but for the invention of the telescope 
could hardly have been much exceeded by his successors.^ 

It will not be out of place to say a few words here about 
a time-honoured absurdity which has attributed great care- 
lessness to Tycho Brahe in the adjustment of his instruments 
in azimuth. In 1671, Picard, when determining the lati- 
tude of Uraniborg, measured the azimuths of the principal 
church spires in Seeland and Scania visible from the site 
of Uraniborg. At Copenhagen he found among Tycho's 
manuscripts similar observations which showed considerable 
differences from his own.* Picard did not lay any stress 
on this discrepancy when mentioning it in the account of 

^ By computing the orbit from the sextant observations alone, Peters found 
the probable error of one distance = iio".5, which result, however, is less 
certain than the one given above. 

^ " Plura enim hie quam ipsa magnitudo necessaria sunt. Nam et materiae 
soliditas, aeris mutationi nihil cedens, & preparationis concinnitas, diuisioniim 
Eubtilitas, pinnaoidiorum atque perpendiculi iusta applicatio, firma fulcra, 
debita, dispositio, conueniens & obsecundans tractatio, accurata coUimatio & 
numeratio : & pleraque eiusmodi, adesse oportet. Quorum tamen vix omnia 
instrumento ligneo, quantsecunque magnitudinis, competere, aut sane non diu 
in eo sarta teota perdurare possunt. Longe igitur preeferendiim censeo e 
solida metallica materia confectum instrumentum." . . . Progymn., p. 635. 

^ By using verniers, improved pinnules, &c.,Hevelius (without using tele- 
scopes) reduced the probable error of a distance measure to 18", to the 
amazement both of contemporaries and of posterity (Lindelbf, Veber die 
Oenauigkeit der von Hevelius gemess. Sternahstande, St. Petersburg Bulletin, 


* They occur in a rough volume of observations, 1578-81, and are copied 
into the volume for 1563-81, so often quoted above in Chapter ii. They are 
entered at the end of the year 1578, hut it is not stated when they were made. 
There are also azimuths measured from a hill and from the church at Hveen, 
probably with a cross-staff, and they are headed, " Observationes geographicse 
in insula Huena factse." 


his journey, probably because he saw from the MS. that 
Tycho had merely measured these approximate azimuths 
for the sole purpose of constructing a map of the island. 
By others the matter was, however, misunderstood ; and by 
some the discrepancy was even supposed to prove a shifting 
of the meridian line between the times of Tycho and Picard ; 
while others have pointed to Tycho as a blunderer in com- 
parison with the builder of the Great Pyramid, who was 
able to orient the sides of that remarkable structure with 
considerable accuracy.'' It was, however, shown by a Danish 
writer, Augustin, that Tycho and Picard had in two cases 
pointed to different spires. At Elsinore Tycho had pointed 
to St. Mary's Church, while Picard had pointed to the taller 
spire of the church of St. Olaus, built in 1 6 1 4 ; and the 
cathedral of Lund has two towers, of which Tycho had taken 
the southern one, while Picard pointed midway between the 
two. This accounted for the most serious differences, and 
the remaining measures would agree well by assuming an 
error of 14', by which amount Tycho's meridian line should 
have deviated from the true south point towards the east. 
Augustin even imagined that he had found in the printed 
observations the proof that Tycho detected this error on 
the 2nd November 1586.^ It is, however, evident from 
the words used by Tycho that he must on this occasion 
have referred to a recent readjustment (in novo meridiano) 
of the instruments at Stjerneborg only, and not to some meri- 
dian line adopted since 1579, at which time (at the latest) 
the azimuths of the church spires were measured.^ The 

1 In his Aoge of Chazelles, Fontenelle had already in 17 10 remarked the 
absurdity of attributing such an error to Tycho, and Montucla had expressed 
himself to the same effect. Hist, des Math., i. p. 669. 

^ Skrifter som udi det Kong. VidensJcabernes Selskai ere fremlagte, xii., 
I779j p. 191 et seq. ; risumd in the Connaissance des Temps pour Van 1820, 
P- (3^5)- Compare Carreap. astron. du, Baron de Zach, vol. i. p. 402. 

' Tycho's words are {Hist. Ccel, p. 170) : "In novo meridiano monstrabant 
armillse 15 M. ante verum meridianum. Quare omnia tempora haotenus 


observations of the comet of 1585, as we have just seen, 
prove conclusively that in that year the great armillse were 
in excellent adjustment, so that Tycho cannot have made 
use of any badly placed meridian mark. I have also com- 
puted a number of observed altitudes and azimuths of stars 
from 1582, and from these it is evident that the zero line 
of the azimuth circle was within i' of the meridian.^ As 
Tycho never once alludes to the use of meridian marks or 
terrestrial azimuth marks (which he could not possibly have 
seen from the subterranean observatory, where stars near 
the horizon could only be observed with portable instru- 
ments in the open air), while he frequently states that he 
verified his instruments by observations, it is impossible 
that he can, even before 1586, have made a mistake of 
14' in azimuth in the adjustment of his numerous instru- 

The astronomical work in Tycho Brahe's observatory 
must have involved a considerable amount of computing, 
even though the great globe, no doubt, was very often used 
for the solution of spherical triangles. Trigonometry had 
made considerable advances in the fifteenth and sixteenth 
centuries, and Tycho could build on the labours of Purbach, 
Eegiomontanus, Copernicus, and others, both as regards the 
solution of triangles and tables of sines and tangents. But 

observata uno minuto tardiora sunt debito, non tamen ubique unius minnti 
est differentia, quia non semper eodem modo se habuit ; ubique dimidii." The 
instrument here referred to is the great equatorial at Stjerneborg ; the hour 
circle had probably been found to be set 15' wrong. On p. 210 (same date] 
Tycho adds to some observations with the quadraiis voLvhilis (also at Stjerne- 
borg) the remark : " Azimutha sunt ex nova restitutione meridiani ante biduum 
facta." In the Connaissance des Temps for 1S16, p. (230), Delambre quotes 
the note to the observation with the mural quadrant of 3rd December 1582 
(Sist. Cod., p. 4), and assumes from this that Tycho in 1582 had found an 
error in his azimuths. The note in question has, however, nothing to do with 
this matter, as it only explains that the recently mounted quadrant had not 
yet been properly fixed to the wall. 

^ See Note F. at the end of this volume. 


logarithms had not yet been invented, and great inconveni- 
ence was therefore felt whenever it became necessary to 
multiply or divide trigonometrical quantities. To obviate 
this difficulty a method was invented, the so-called Prosta- 
phseresis,-^ by which addition and subtraction were sub- 
stituted for multiplication and division, and in the history 
of this invention, which was made independently by several 
mathematicians, the name of Tycho is also mentioned. The 
Arabs had had an idea of this method ; at least, Ibn Tunis 
makes use of the formula^ 

cos A cos B = J [cos (A-B) + cos (A + B)] 

but, like many other discoveries of the Arabs, this formula 
had to be deduced anew in Europe. It was found by Viete, 
as well as the corresponding formula : 

sin A sin B = J [cos (A-B) - cos (A + B) ] 

but as Vi^te's Canon Mathematicus, which was published in 
1579, seems only to have been printed in a few copies at 
his own expense, it is very possible that Tycho Brahe 
never saw it, or at least that he had not seen it in 1580, 
when, according to Longomontanus, he and Wittich invented 
Prostaphseresis.' This was among the inventions which 
Wittich a few years later brought to Cassel, where Biirgi 
soon developed the method further. It appears that Wittich 
merely had shown him the above formula for sin A sin B ; 
but Biirgi applied the principle to the formula of spherical 
trigonometry, and ultimately was led to discover logarithms 

^ Astronomers need hardly be reminded that this word (formed from irpbaBecn^, 
addition, and d<f>alpe(ris, subtraction) had originally signified the equation of 
the centre, in which sense it was still used by Tycho. 

^ Delambre, Astr. du Moyen Age, pp. 112 and 164. 

' Si autem de hujus compendii inventore quis quasrat, nee Arabes aut 
Joannem Kegiomontanum fuisse, soripta eorum analemmatioa declarent ; 
neminem certe habeo Tychone nostro & Vitiehio Vratislaviensi antiquiorem : 
quorum scilicet mutua opera primum anno 1582 [should be 1580] in Husena, 
sphserioa qusedam triangula tali pragmatiae pro studiosis Vranicis sunt 
subjecta." — Jjongomontani Astr. Danica, p. 8. 


years before Napier did ; but, as is always the case with that 
remarkable man, without securing the priority by a timely 
publication.'^ At Uraniborg the method did not make any 
progress after the departure of Wittich, and it is therefore 
more likely that it was he, and not Tycho, who was the 
inventor, as he is known to us (through the repeated 
testimony of Tycho) as an able mathematician. In 1 5 9 1 
a short treatise on plane and spherical trigonometry was 
drawn up at Uraniborg, but it does not indicate that Tycho 
had developed trigonometry in any way, as the rules are 
similar to those given in other treatises of that day, and 
are frequently expressed in even clumsier language than 
usual at that time.^ The demand for the facilities offered 
by the Prostaphaeresis was, however, so great, that Reymers 
Bar, Clavius, Joestelius, Magini, and others, with more or 
less success, continued to work in this direction, until the 
method was driven from the field by the discovery of 

We have followed Tycho Brahe through his chequered 
career, and we have reviewed his scientific labours. No 
doubt his contemporaries were not uninfluenced in their 
estimation of him by his princely residence, with its tasteful 
decoration and wonderful observatories, and also by its singu- 
lar situation on the little island, which contributed to exhibit 
the noble astronomer in a romantic light. But while these 
circumstances threw a halo over Tycho even before his works 
had become known beyond a limited circle, posterity has 
hardly been influenced by considerations like these when 

^ R. Wolf, Astr. Mittheilungen, No. 32 ; Gesch. d. Astronomic, p. 348 
et seq, 

^ In the University Library at Prague, published in facsimile by Studnicka 
at Prague in 1886 : " [Tychonis Brahe] Triangulorum planorum et sphaerioorum 
Praxis arithmetica." The.original is written on twenty leaves, inserted at the 
end of a copy of Rhetici Canon doctrinw triangulorum. Tycho has written his 
name under the title of the MS., but the handwriting of the remainder does 
not seem to be his. 


affirming the judgment of his time. | He not only conceived 
the necessity of supplying materials for the discovery of the 
true motions of the heavenly bodies, and by his improve- 
ment of instruments and accumulation of observations made 
it possible for Kepler to reach this goal, but in almost all 
the branches of practical and spherical astronomy he opened 
new paths, and made the first serious advance since the days 
of the Alexandrian school. / Hereby he showed his superi- 
ority to the Landgrave ;^^for though the latter had perceived 
the necessity of systematic observations at least as early as 
Tycho did, he confined his attention almost entirely to the 
fixed stars, and had to borrow the improvements in instru- 
ments from Tycho, and let them be worked out by the great 
mechanical talents of his assistant, Biirgi, before his observa- 
tions could rival those of Tycho in accuracy. It was, 
therefore, not at Cassel, but at Uraniborg that the reform of 
practical astronomy was carried out, and posterity has not 
thought it an exaggeration when one of the greatest 
astronomers of the nineteenth century spoke of Tycho Brahe 
as a king among astronomers. ■*• 

•■ Bessel, Pojpuldre Vorlesungen, p. 422. 



It was perhaps well for Tycho Brahe that his career in 
Bohemia was cut short, for he would sooner or later have 
been bitterly disappointed in the faith he had placed in 
the Emperor's promises. His greatest wish had always 
been that the observatory work should not cease at his 
death, but that some competent person might be appointed 
to carry it on ; but though Kepler, two days after Tycho's 
death, was informed by Barwitz that he was to be the new 
Imperial mathematician, the observations with Tycho's instru- 
ments were not continued very long. The Emperor soon 
agreed with Tycho's family to purchase the instruments for 
the sum of 20,000 thaler; but when Tengnagel came back 
. to Prague in the summer of 1 602, he assumed the position 
of Tycho's scientific heir, promised the Emperor to have 
the Eudolphine tables finished within four years, and though 
Kepler had commenced to observe Mars, he was deprived 
of the instruments, which were stored away in a vault under 
Curtius' house. Kepler never got access to them again, 
of which he complains repeatedly in his writings.^ They 
seem to have been preserved in this manner until the year 
1619, when the Bohemians rose against the House of Habs- 
burg and elected Frederic V., Elector Palatine, their king, 
and during the disturbances which followed, some of the 
rebels are said to have destroyed the instruments as Imperial 

' Opera, ii. p. 760 (in the dedication to Hoffmann of the book on the star 
in Cygnus), and p. 755. In the book on the star in Serpentarius (ibid., ii. 656) 
Kepler quotes a few observations by Tengnagel, "in viridario Cffisaris, ubi 
deposita habebantur instrumenta Braheaiia." Perhaps they had then (October 
1604) been brought back to Ferdinand I.'s villa. In December 1601 and May 
1603 Kepler used one of Tycho's clocks in observing two lunar eclipses [Opera, 
ii. p. 3to). 



property.! The great globe alone was saved, and was in 
1632 found at Neisse, in Silesia, at the College of the 
Jesuits, by Prince Ulrik, a son of King Christian IV. of 
Denmark, who was in the service of the Elector of Saxony, 
and had taken Neisse by storm. How or when the globe 
had been sent there is not known, but Prince Ulrik now 
sent it to Denmark, where it was first kept at the Castle 
of Rosenborg, then at the University,^ and afterwards in 
a room of the Round Tower which had been erected in 
Copenhagen to serve as a University observatory, and was 
finished in 1656. An inscription, composed by Longo- 
montanus, was attached to the globe or to the wall of the 
room, and the beautiful monument of the great astronomer 
remained at the Round Tower till October 1728, when it 
was unfortunately destroyed in the great conflagration, in 
which, among many other things, Ole Rbmer's unpublished 
observations perished. At the present day there is neither 
at Prague nor at Copenhagen the smallest vestige of Tycho's 
celebrated instruments.^ 

Tycho's wife and children all remained in Bohemia, pro- 
bably because they were honoured and respected there, while 
the difficulty which they found in obtaining payment for 
the instruments must also have tied them to Bohemia, as 
they must have known well that they would have no chance 
of getting their money unless they remained on the spot. 
Tycho's widow died in 1604, and was buried beside her 
husband, as we have already mentioned. A year or two 
before her death she had purchased a country property 
towards the Saxon frontier, and her eldest son, Tycho, had 
in March 1604 married the widow of a country gentleman 
in the same neighbourhood. He became the father of five 
children, and died in 1627. His younger brother Jorgen 
(George), died in 1640. Magdalene Brahe, Tycho's eldest 
daughter, apparently never married ; of the second daughter, 
Sophia, nothing is known except that she became a Roman 

1 Gassendi, p. 216.' 

^ Where Huet saw it in 1652 {Commentarius, p. 81). 

5 The inscription is given by Gassendi, p. 217; Weistritz, 5. p. 217. At 
the Prague observatory (founded in 1751 in the Clementinum, far from Tycho 
Brahe's observatory) there are two sextants and a clock showing the Tychonic 
system, which are supposed to have belonged to Tycho Brahe ; but they show 
no sign of Tycho's refined workmanship, and the two sextants (the larger of 
which is said to have been made for him in 1600 by Erasmus Haberniel) have 
not his peculiar pinnules. There is no proof of their ever having belonged 
to Tycho Brahe (Astron. meteorol, und magn. Beobachtungen an der Sternwarte 
zu Prag im Jahre 1 880, p. iv. ). 


Catliolic. The youngest daughter, Cecily, married a Swede, 
Baron Gusta£F 8parre, colonel of a German regiment, and 
died at Krakau. In 1630 some of Tycho Brahe's nearest 
relations in Denmark, among whom was his sister Sophia, 
issued a declaration, stating that Christine, by the ancient 
laws of the kingdom, "on account of the open, unchanged, 
and honourable life of both of them, must be acknowledged 
as his wedded wife." ^ 

Tengnagel very soon gave up the idea of working at the 
Eudolphine tables. He had probably only been a short 
time at Uraniborg (he is mentioned as an unpractised 
observer in September 1595), and there are no signs of his 
having occupied himself seriously with astronomy during 
Tycho's lifetime, so that probably it was only jealousy of 
Kepler which induced him to prevent the latter from taking 
up Tycho's work at once. He was in 1605, by the Emperor, 
made a Councillor of Appeal, and received a grant from the 
Benatky estate " for his astronomical observations," and he 
was also employed on various foreign embassies — among 
others, to England, whither he was accompanied by Eriksen, 
who also gave up astronomy.^ Tengnagel was appointed 
Councillor to Eudolph's cousin, Leopold, Bishop of Passan, 
and afterwards became a privy Councillor to Ferdinand II. 
He was the only one of the family who was allowed to 
remain in Bohemia after the battle of Prague (November 
1620), when the Protestants were driven from the Austrian 
possessions. His wife, Elizabeth Brahe, had died in 161 3, 
leaving several children. He died in 1622. 

Notwithstanding his connection with the two Emperors, 
Tengnagel had been unable to get the purchase-money for 
the instruments paid in full. From a letter which Magda- 
lene Brahe wrote to Eske Bille in July 1602 we learn that, 
although the Emperor soon after Tycho's death had agreed 
to purchase the instruments for 20,coo thaler, he was, as 

* The document was written in German, so that the children of Tycho 
could make use of it in Bohemia and Saxony, where they all lived. Danske 
Magazin, ii. p. 367 ; Weistritz, ii. p 375. Sophia Brahe died in 1643 "* the 
age of eighty-seven. She was the only one of Tycho's brothers and sisters on 
whom some of his glory was reflected, and when she, nine years before her 
death, at Elsinore, met a French embassy, the secretary, Charles Oger, in the 
description which he afterwards wrote of his journey, mentioned the meeting 
with her among the most remarkable events. 

^ Eriksen observed the solar eclipse of October 1605 in London, and brought 
letters backwards and forwards between Kepler and Harriot. He had early 
in 1602 (with Tengnagel) visited jFabricius in Ostfriesland, and afterwards for 
sometime assisted Kepler {Opera, iii. 533, ii. 432). 


usual, without money, and had in vain tried to get the 
Bohemian Estates to pay the sum, which they declined to do, 
on the plea that this was a private matter of the Emperor's ; 
and he attempted to persuade the heirs to accept some more 
or less doubtful securities instead of ready money.^ This, 
however, they would not do, and in September 1603 they 
got 4000 thaler paid from the royal revenues. Owing to 
the disturbed state of Bohemia and the subsequent great 
war, the family apparently never received any part of the 
remaining 15,000 thaler, though they persevered for many 
years in their applications to the Government. The last 
time anything bearing on this matter is mentioned is in 
1652, when it is stated that a married daughter of the 
younger Tycho had been six years in Bohemia on a safe- 
guard from the Elector of Saxony, endeavouring to get her 
share of the money due from the Treasury.^ 

The first piece of work which Kepler undertook after 
Tycho's death was to get the Progymnasmata published. 
The section about the lunar theory was not yet printed, 
but the woodcuts were ready and the text completed in 
manuscript. A postscript seemed desirable, explaining how 
the book had been written and printed by degrees, and 
Kepler at once wrote this appendix, which fills six pages.^ 
He first explains how Tycho's anxiety that the book should 
contain the latest results of his investigations had made him 
push on with the printing before the whole manuscript was 
ready (it had been prepared in the years 1582-92). A few 
slight discrepancies are pointed out between these latest 
results and a few passages in the book, concerning the 
moon, but printed long before. It is also remarked that 
in the first chapter the planetary inequalities are referred 
to the sun's mean place, while it had recently been found 
in the case of the moon and Mars that it is the apparent 

' Danske Magazin, ii. p. 36 1 ct seq. ; Weistritz, ii. p. 369 ct seq. Erom this 
letter it appears that the family had previous to July 1602 left Curtius' house, 
and lived in the part of the city called Altstadt. They had commenced to 
remove the instruments to their new residence, as they had not yet received 
any payment ; and even of Tycho's salary, which the Emperor had ordered to 
be paid up to the date of his death only, there were still a thousand florins 
owing to them. In April 1 608 Magdalene wrote a letter to Longomontanus 
(ibid.) giving him information about the family. 

2 Por full particulars about these transactions see the paper by Dvorsky, 
quoted above, p. 307. 

^ That Kepler is the author of this appendix is stated by himself in a letter 
to Magini {Opera, iii. p. 495 ; Carteggio, p. 331) ; it is reprinted in Opera, vi. 
p. 56S. 


place which enters into the equations, so that the same 
doubtless also was the case with the other planets. Lastly, 
the recently noticed fact that the solar excentricity is only 
half as great as formerly believed, is referred to. A dedica- 
tion to the Emperor from Tycho's heirs, a short notice to 
the reader (stating that the author had intended to write 
a preface on the utility and dignity of astronomy), and the 
privileges of the Emperor and James VI. were also printed, 
and the book was published in the autumn of 1602. The 
title is: "Tychonis Brahe Dani Astronomise instauratse 
Progymnasmata. Quorum hsec Prima Pars de restitutione 
motuum Soils & Lunte, Stellarumque inerrantium tractat. 
Et prseterea de admiranda noua Stella Anno 1572 exorta 
luculenter agit. Typis inchoata Vraniburgi Danite, absoluta 
Pragas Bohemia MbOII " (some copies have MDCIII). The 
book seems to have been printed in 1 500 copies,^ and most 
of these appear to have been afterwards sold to Gottfried 
Tampach, a well-known bookseller in Frankfurt, who, in 
16 10, issued the book with a new title-page and the begin- 
ning as far as p. 16 reprinted.^ 

The second volume of the Progymnasmata had, as we have 
seen, been quite ready since 1588, though Tycho had only 
presented a few copies to correspondents, and had intended 
to add an appendix on Craig's allegations about the parallax 
of comets. This he had never done, and the book was now 
published in 1603 with a new title-page, and a dedication 
to Barwitz from Tengnagel, as well as a preface to the 
reader.^ Like the first volume, it was re-issued by Tampach 
in 16 10 with a new title-page, and the first seven leaves 
(including Tycho's own preface) and the two last pages 
reprinted.* The issue of 16 10 is generally found bound 
together with the first (and only) volume of the Upisiolce, 
printed in 1596, furnished with a new title-page, but retain- 
ing the original colophon. Tampach had probably acquired 
the stock of copies of the Upistolce on the death of Levin 

' Tycho inquired in January 1600 if he could get the sheets yet wanting 
printed at Gorlitz in 1500 copies. Aiis T. Brake's Brief wechsel, p. 16. 

^ The misprints so far are corrected by the list of errata at the end of the 

^ The title is the same as given above on p. 163, except that instead of the 
last sentence it has : " Typis inchoatus Vraniburgi Danise, absolutus Pragffi 
Bohemise." The colophon is the vignette "Despiciendo svspicio," and under- 
neath : ".Pragae Bohemorum. Absolvebatur Typis Schumanianis. Anno 
Domini MDCIII." 

■* The two volumes were reprinted in Frankfurt in 1648 with the title T. 
Brahei Opera Omnia. This is a very poor edition with very small print. 



Hulsius of Niimberg, a well-known writer and publisher, 
to whom the heirs would seem to have sold them, as some 
copies have on the title-page : " Xoribergre, apud Levinnm 
Hulsium MDCI." 

The stock of copies of the Astronomicc instauratcc Mecha- 
nica appears to have been exhausted, but most of the wood- 
cuts and copper-plates were in the possession of the heirs, 
who sold them to Levin Hulsius. He printed a neve edition 
at Nurnberg in i6o2, exactly like the original, but with 
narrower margins, and without the neat border which in 
the original runs round the pages. Paper and print are 
also somewhat inferior, and Tycho's portrait is on the title- 
page substituted for the vignette of the original. 

On the state of Tycho's other manuscripts Kepler drew 
up a short report,^ from which it appears that the printing 
of the second volume of letters had been commenced, and 
that Tycho had thought of adding some astronomical tables 
to the volume to make it more saleable. Kepler suggested 
that matter of astronomical interest occurring in the un- 
printed letters might be extracted and printed, so that the 
sheets already in print would not be wasted. This was, 
however, not done, and only a few of the letters have yet 
been published. For the third volume of Progymnasmata 
(on the comets of 1582, 1585, &c.), the materials were ready, 
but nothing was put into shape. As to the Tabula: Rodol- 
phece, Kepler stated that the materials were abundant, " nee 
deerunt ingenia, si Maecenates sint, et exiguum aliquid in 
certis pensionibus annuis in hunc usum erogetur." The 
Thcatrum astronomicum (of which Tycho had sketched the 
plan in his letter to Peucer in 1588^) should contain the 
theory on which the tables were based, but nothing of it 
had been written. 

It seems that Kepler received Tycho's observations, 
originals and copies, after signing a contract with Teng- 
nagel in 1604. He found them so indispensable to his 
studies that he never returned them, but it was not for- 
gotten that they were in his possession, and in November 
1 62 1 (when he had been obliged to stay more than a year 
in Wiirtemberg to watch the trial of his mother for witch- 
craft) Ferdinand II. wrote to the Duke of Wiirtemberg 
requesting him to command Kepler to return the manu- 
scripts.^ Kepler was probably back again at Linz (where he 

' Kcpleri Opera, i. p. 191. - See above p. 182. 

s Breve off Ahtstt/Mei; p. 150. 


had lived since 1612) when the letter arrived in Wiirtem- 
berg, and it had no effect. After publishing the Tahulce, 
Rudolphinw in 1627, he thought the following year, while 
living at Sagan, in Silesia, under Wallenstein's patronage, of 
getting the observations printed. He wrote on the 17th 
August 1628 to Jorgen Brahe that he hoped soon to com- 
mence the printing, but as he had found a selection from the 
observations of the years 1600 and 1601 inserted in Snellius' 
edition of the Landgrave's observations,^ he inquired if Brahe 
still had the originals for those two years, or whether Snellius 
could have got hold of them, so that his widow might have 
them still.^ Nothing came, however, of the intended edition, 
and the original observations remained in Kepler's possession, 
and after his death in that of his son, the physician, Ludwig 

But while Kepler retained the originals as pledges for the 
considerable arrears of salary due to him, a set of unfinished 
copies in quarto volumes had remained in Austria.* These 
volumes are alluded to by Tycho Brahe in his Mechanica (fol. 
Gr. 2), where he mentions that the observations had been 
entered in large volumes, and afterwards, for each year, 
copied into separate volumes and sorted according to subject 
— the sun, moon, planets (beginning with Saturn and ending 
with Mercury), and the fixed stars. Albert Curtz, a Jesuit, 
and Rector of the College of Dillingen, on the Danube, who 
had corresponded with Kepler both on scientific and religious 
subjects, conceived the idea of publishing Tycho's observa- 

' " Ooeli et siderum in eo errantiuin observationes Hassiacse . . . et speci- 
legium bieniiale ex observationibus Bohemicis V. N. Tychonis Brahe." Lugd. 
Batav., 1618, 4to. Snellius had as a youth of twenty paid a short visit to 
Prague in 1599 or 1600. See K Wolf's Astr. Mitth., Ixxii. 

^ Breve og Aktstykher, p. 152. About Kepler's intention of publishing the 
observations, see his Opei-a, vi. pp. 616, 621, vii. p. 215 (in his book T. Brahei 
Hyperaspistes, Prankfurt, 1625, against Scipione Chiaramonte, who in his 
book Antitycho had tried to prove from Tycho's own works that comets are 
sublunary), also viii. p. 910. Gassendi, p. 207. 

^ On the outside of the cover of the volume for 1596-97 (bound in old 
music-paper) there is pasted a slip of paper on which Kepler has written : 
"Extract aus mein Johan Kepplers den Brahischen Brben zugestelter Erkle- 
rungsschrift. Entlich und zum fiinften sol auf einera jedem Tomum herab- 
gemeldeten Observationen, sobalt ich nach Linz komme ein offene Zettel 
auffgeleimet, und raeinen Erben, darinnen von mir anbefohlen werden, dass 
solche Biicher, da ich etwa Todtes verbliche, absobalden zu meinem Schatz 
oder Kleinodien eingesperret und vor der Eroffnung Jhr. Kay. May. so wie 
auch denen Brahischen Erben, umb weitere Vorsorg und Verwahrung dero- 
Bblben angemeldet werden, damit also die Erben auch auff diesem Eall, de 
abgesetzten ersten Puncts halb^n desto mehr versichert sein." 

' Or perhaps they were purchased from Kepler's daughter, if the MS. account 
printed by Kastner is authentic {Geschichte d. Math., ii. p. 651 et seq.). 


tions from these volumes. It is very strange that he should 
not have made any serious effort to obtain the originals, as 
he was engaged on the work already before 1647, in which 
year Gassendi heard of the undertaking ; while Hevelius in 
the following year inquired how the rumonr could be true 
that a Jesuit had got Tycho's observations from the Emperor 
and was about to publish them, since Hevelius with his own 
eyes had seen the original observations from 1564 to 1601 
in Ludwig Kepler's house at Konigsberg. Curtz himself 
seems, however, to have believed that the nineteen annual 
volumes for the years 1582-92 and 1594-1601, which he had 
before him, were originals and not copies, and though he 
suggests that they were the set of twenty-one volumes 
referred to by Tycho in the Appendix to the Meclianica (fol. 
H. 4), it does not seem to have occurred to him that in that 
case not only the volume for 1 593, but five earlier volumes 
must have been lost, since Tycho wrote the Mcchaiiica in 
1 597. The volumes which he used, and which he describes 
as being ornamented on the cover with Tycho's portrait and 
arms,i were therefore copied, and the observations of 1582 
printed in 1656 as a specimen,^ after which the complete 
Historia Ccelestis was published at Augsburg in 1666 in a 
handsome thick folio volume, on which the editor, instead of 
his own name, Albertus Curtius, has called himself anagram- 
matically Lucius Barrettus.^ 

The various astronomical observations, chiefly of eclipses 
anterior to Tycho's time, as well as the observations of the 

' Like the presentation copies of the Mechanica (above, p. 261). The nine- 
teen volumes are still in the Hofbibliothek at Vienna, where there is also a 
miscellaneous collection of loose leaves or small stitched books with computa- 
tions, notCF, or letters. Some of the letters have been published of late years 
{Tychonis Brahei et ad eum doet. vir. Apist.). A list of the MSS. was made by 
Priis in 1868, but owing to his complete ignorance of the subjects referred 
to in them, it is of little use (Danske Samlinger, iv., 1S69, p. 250). 

^ " Sylloge Ferdinandea sive collectanea historise coelestis ex commentariis 
MS. obss. Tychonis Brahei ab anno 1.582 ad annum 1601. Accessit epime- 
tron ex obs. Hassiacis, Wirtenbergicis et aliis . . . vulgavit Lucius Barrettus, 
anno 010 oic LVi Viennse Austrise." Contains the preface and Liber prolego- 
menus and the observations of 1582, headed on every page : "Sylloge Ferdi- 
nandea." Different print from the Ilist. Ccel. At the end of tlie \ ulume is 
the colophon : " Operis Davidis Havtii, Bibl. Viennensis, anno l657'" 

^ "Historia Coelestis complectens Observationes astronomicas varias ad 
Historiam Coelestem spectantes 111. viri Tychonis Brahe, Babylonicas, Grjecis, 
Alexandrinas, Moestlini observationes Tubingenses, Hassiacas, &c. Aug. 
Vind. i655" (also with title-page on which "Ratisbonse, 1672"). Large plate 
with four emperors, more or less imaginary views of Uraniborg, Wandesburg, 
Benatky, Horti Ceesaris and Domus Curtii, most of Tycho Brahe's instru- 
ments, &c. cxxiv. + 977 pp. fol. 


Landgrave, Mastlin, and others, whicli Curtz inserted in this 
volume, are not without value and interest, but Tycho Brahe's 
observations are presented in so mutilated and distorted a 
shape as to be well-nigh useless. Not only is there no ex- 
planation why the volume begins with the year 1582 (which 
has led many writers to believe that Tycho had not observed 
regularly until then), but it is evident that the copy at the 
disposal of Curtz had never been finished nor collated with 
the originals. Frequently several consecutive pages have 
been passed over, so that the volume is very far from contain- 
ing a complete record even for the years it pretends to cover. 
For instance, at the end of 1584, half the observations made 
by Elias at Frauenburg and all those he made at Konigsberg 
are omitted. Again, in 1589 and 1591 there are several large 
gaps in the observations of fixed stars, similarly in 1595 and 
1597, while the omissions of one or two nights' work are very 
numerous indeed. But this is far from being the worst fault. 
There is scarcely a column which is not full of errors, figures 
misplaced or left out, words like dexter and sinister, horealis 
and meridionalis, are interchanged ; sometimes the signs of 
the zodiac have even been mistaken for figures, so that the 
sign of Cancer becomes 69, &c. In short, the work is not 
far from being an Augean stable. Unfortunately there is no 
other edition of Tycho Brahe's observations except of the 
observations of planets made in 1 593 1 and of the observations 
of comets. The Historia Ocelestis gives the reader a fair idea 
of the general scope of Tycho's work, but it cannot be used 
for any scientific purpose. 

In the meantime the original observations, of the existence 
of which Curtz was ignorant, were (at the latest in the begin- 
ning of 1662) by Ludwig Kepler sold to King Frederick 
III. of Denmark, who deposited them in the newly founded 
Royal Library at Copenhagen, where they are still preserved. 
King Frederick soon after decided to have them published 
under the direction of the mathematician Professor Erasmus 
Bartholin, under whom six students were employed in copy- 
ing and collating, while the necessary pecuniary means were 
liberally supplied. A complete copy had been made and 
carefully read with the originals, when Bartholin heard of the 
publication of the Historia Ocelestis, and obtained a copy of it. 
As he found it extremely defective and erroneous, he pub- 

' To account for the absence of these, Curtz invented a fable about the 
volume for .1593 having been sent to Caseel and thereby lost, which has been 
repeated by uiauy writers. 


lished in 1668 a critique of it, showing the errors in tlie 
observations of 1 582, and announcing the forthcoming correct 
edition.! Bartholin furthermore compared a copy of the 
Historia Ccelestis (hound in two volumes) with the originals, 
and entered in it all the corrections and smaller omissions, 
while he in a third volume had the observations previous to 

1582, the longer omissions, the year 1593, and tlie observa- 
tions of comets, carefully copied and compared with the 
originals.^ In 1669 he caused inquiries to be made from 
Blaev, in Amsterdam, about the printing of the new edition, 
which Blaev seemed disposed to undertake.^ 

Unfortunately, King Frederick III. died in 1670, and as 
his son and successor took no interest in literature or science, 
there was an end to the prospect of a correct edition of 
Tycho Brahe's observations. In the following year Picard 
came to Copenhagen to determine the geographical position 
of Ui'aniborg, and on learning how matters stood, he begged 
and obtained leave to take Bartholin's copy back with him 
to Paris to have it printed at the expense of Louis XIV.* 
For the sake of control during the printing, the originals 
were handed to Bartholin's assistant, Ole Eomer, whom 
Picard had persuaded to go with him to France. The 
printing was commenced at Paris, but Louis XIV.'s wars 
required money, and the undertaking was eventually stopped.^ 
Inquiries were made for the original manuscripts by the 
Danish Government in 1696, and they were found in charge 

' " Specimen recognitionis nuper editarum observationum astronomioarnm 
n. V. Tyehonis Brahe, in quo recensentur insignes maxime errores in editione 
Augustana Historise Ccelestis a. 1582 ex collatione cum autographo . . . ani- 
madversiab Erasmo Bartholino." Hafniae, 1668, small 410,48 pp., of which 
6 pp. are dedication to the King, 11 pp. introduction, and the remainder 
errata. Reviewed by Kastner, ii. p. 656. 

" Strange enough, he did not copy the year 1581, but instead of it the year 

1583, though this is in the Hist. Ccel. About this supplement, see Bugge, 
Vbservationes astronomicce, 1781-83, Hafniae, 1784, p. xviii., where a cata- 
logue of Tycho's original MSS. is given. See also below, Note H. 

^ Werlauff, Uistoriske Efterretninger cm det store hongdige Bibliotheh, 
KjiJbenhavn, 1844, P- 4ii- 

* Picard gave the following receipt for them (copied by Bartholin into the 
supplementary volume) : " Jeconfesse avoir recue de Mons. Erasme Bartholiu 
les observations de Tycho Brahe escrites au net en cinq Volumes in folio 
depuis I'annee 1563 jusques h 1601 avec les Observations des Cometes, h, condi- 
tion qn'ils seront imprim^es h, Paris au Louvre aux depens du Roy de France, 
& quant a la Dedication & Preface elles seront faites par le dit Mr. Bar- 
tholin. Je promets aussy, qu'incontinent aprfes I'ouvrage acheve d'imprimer, 
il en sera fourny cinquaute exemplaires, qui seront mis entre les mains de qui 
Ton voudra. Fait h, Copenhague, le 2 Avril 1672. Picakd." 

5 Sixty-eight pages were printed (as far as 1582). See Lalande's Astrommie 
(2nd edit.), i. p. 198. 


of La Hire at the Paris Observatory.^ They were handed 
over to the Danish envoy in 1697, but were not sent back 
to Copenhagen till his return to Denmark ia 1707. Being 
deposited in the Royal Library, they fortunately escaped the 
great fire of 1728, in which the University Library and the 
Observatory (with Eomer's observations) were destroyed. 
In 1707 it was suggested by Dr. Arbuthnot, physician to 
Prince George of Denmark, that Tycho's observations ought 
to be printed in England, together with those of Flamsteed, 
and Newton drew up a letter to Piomer on the subject, but 
nothing further came of it.^ Bartholin's copy remained in 
Paris at the Academie des Sciences, and is now at the Paris 
Observatory.^ La Hire had copied the observations of 
1593 from the originals, and they were published in the 
Mimoires de I'AcacUmie for 1757 and 1763. De I'lsle 
had made a copy of the whole series, translated into Prench, 
but with frequent omissions, which is now also deposited at 
the Paris Observatory. Pingre made extensive use of it for 
his Comitographie.'^ 

While Tycho's observations were thus turned to lasting 
account, there is scarcely a trace left of the magnificent build- 
ings he raised at Hveen. 

" Est in conspectu Tenedos, notissima fama, 
Insula dives opum, Priami duin regna manebant, 
Nunc tautum sinus et statio male Ma carinis." 

It would almost seem that Tycho did not build in a very 
substantial manner, for already in 1599 Eske Bille wrote 
to him that the farm buildings would soon tumble down, 
and that the forge was also in a very bad state, for which 
reason the clergyman wanted to know whether he might 
use the materials to repair the rectory, which already some 
years before had fallen into disrepair. Tycho answered 
that the clergyman had no claims on him, and had behaved 
very badly, and the peasants had been stealing building 
materials from the rectory. " As to the farm and the castle 
itself being in bad repair, I can only say, as I have done 

1 Danisehe Bibliotheh, viii. p. 684 ; Werlauff, I. c, p. 57 ; Oiservationes 
septem Oomefarum (1867), p. iii. 

^ Brewster's Memoirs of Sir I. Newton, ii. p. 168. 

3 M. Bossert of the Paris Observatory informs me that this copy is in six 
volumes (which agrees with Picard's receipt), in 4to, carefully written, the 
observations of comets being by themselves. The title is : Tychonis Brake 
Thesaurus observationum astronomica/rum. 

* Pingr^ i. p. 517 ; Lalande, i. p. 199. 


before, that I do not intend to go to any farther expense 
about it ; there was far too much spent on it before, and if 
I had the money back, it should hardly be so badly spent." ^ 

Soon after Tycho's death, in May 1602, Cort Barleben 
received Hveen in fief, and shortly afterwards he was granted 
permission to pull down the forge. His successor was a 
mistress of the king's, Karen Andersdatter, who got the 
island in 1 61 6, and was followed by her son, Hans Ulrik 
Gyldenlove, who died in 1645, and seems to have been 
succeeded by some nobleman's widow. The destruction of 
Uraniborg had in the meantime gradually proceeded, as there' 
was nobody to look after it. A new dwelling-house was 
erected on the site of Tycho's farm, called Kongsgaarden, 
which stood for about two hundred years, but has now dis- 
appeared, so that only some farm buildings remain. This 
Kongsgaard was built of the bricks and stones of Uraniborg, 
as a mason in 1623 was paid for 60,000 bricks which he had 
" pulled down and renovated from the old castle Oranien- 
borg." ^ In 1645 Jorgen Brahe, a nephew of Tycho's, was 
granted permission to remove " any stones with inscriptions 
or other carved figures or characters " which might be found 
at Hveen.^ Perhaps Tycho's nephew was anxious to secure 
some slight relic of his uncle before it was too late, for a couple 
of years later, when Gassendi inquired about the island, he 
was informed that there was only a field where Uraniborg had 

In 1652 the island was for the first time after 1597 
visited by a man of distinction. Pierre Daniel Huet, after- 
wards so well known as the editor of the classics "in usum 
Delphini," and sometime Bishop of Auranches in Normandy, 
was a young man of twenty-two when, in 1652, he accom- 
panied the learned Bochart, who had been invited by Queen 
Christina to join the galaxy of learned foreigners at Stock- 
holm. Passing through Copenhagen, Huet paid a visit to 
Hveen, and found scarcely a trace of the buildings. In his 
autobiography, which he did not draw up till more than 
sixty years later, when he says himself that both his senses 
and his memory were impaired after a serious illness, Huet 
adds the very absurd statement that neither the clergyman 

' Breve og AktstyJcker, pp. 53 and 104. 

^ Vandalism of that kind is not confined to any age or nation, but the de- 
struction of many a fine old monastery or chapel in the heat of the Reforma- 
tion had made people at that tim.e partioulariy callous to the pulling down of 
historical relics. 

* Friis, Tyge Brahe, p. 30S. 


nor the other inhabitants of Hveen had ever heard the name 
of Tycho Brahe, except one old man, who did not give a flat- 
tering account of him. Successive writers down to the present 
day have quoted this story without noticing the absurdity of 
the idea that a small community of a few hundred people 
should in the course of fifty years have quite forgotten the 
man who raised such fine and singular buildings and was 
visited by kings and' princes.'- 

A few years after, Hveen ceased to belong to Denmark. 
In February 1658 the Danish king was forced to conclude the 
humiliating treaty of Roskilde, by which the provinces east 
of the Sound, which from before the dawn of history had been 
Danish, were handed over to Sweden. King Carl Gustav, 
who was not content with what he had got, but soon after 
made an inefi'ectual attempt to take the whole of Denmark, 
claimed Hveen as belonging to Scania, because the inhabi- 
tants were now under the jurisdiction of the court of Lund.^ 
The spot where Tycho had lived and worked was thus torn 
froin the country which had so little valued him, and, like 
Scania, the island soon became perfectly Swedish — a very 
natural consequence of the close afiinity between the two 
nations, rivals for so many centuries, but now animated only 
by brotherly feelings. 

In 1671 the Academie des Sciences sent Picard to Hveen 
to determine the geographical position of Uraniborg. The 
foundations were still easily recognised, and the earthen walls 
round Uraniborg untouched, except that a stone wall had 
been built across the enclosure, cutting off the north-eastern 
wall and a little of the two adjoining ones, and the parts 
thus cut off had been nearly obliterated by ploughing. Of 
Stjerneborg he saw nothing except a slight hollow in the 
ground, and he did not trouble himself about making exca- 

1 I have looked through the Gazette de France for 1652, in the hope that 
Huet might have sent a letter from Stockholm in which he might have 
described his trip to Hveen. But there is nothing from him or about him, so 
that the only account is the one given in his book Petri Danieli Buetii, 
Episcopi Abrincensis, Commentarius de rebus ad eum pertinentibus, Amster- 
dam, 1718, I2mo, p. 86 et seq. As perhaps hardly one of the writers who 
have copied Huet's story from Weidler's Historia Astronomice have seen it, 
I have quoted it in Note G. The proverbial "oldest man in the parish," 
from whom Huet got his information, attributed the destruction of the 
buildings to weather and the carelessness of Tycho's successors. 

^ Peder Winstrup, Bishop of Lund (son of the Bishop of Seeland of the 
same name), is said to have produced many arguments to support the claims of 
the Swedish king, who had the best possible argument — the sword. Hofmann, 
Portraits historiques, vi. partie, p. 8. About the change of jurisdiction, see 
above, p. 88. 


vations.^ Dnring tlie eighteenth century the ruins werQ 
occasionally mentioned by travellers, but nobody seems to 
have explored them.^ About 1740 a stone with a Latin 
inscription was removed from the site of Tycho's paper-mill 
to his old home at Knudstrup, from whence it was later 
brought to the museum at Lund. In 1747 a cellar was 
accidentally found on the site of the servants' dwelling, at 
the north angle of the wall enclosing Uraniborg. It is 
still to be seen, and if the statement on Braun's map be 
correct, that it was used as a gaol, it can certainly not have 
been a pleasant abode, though doubtless not worse than other 
dungeons of those days. 

Within the present century the ruins at Hveen have 
been more thoroughly examined. They suffered a further 
desecration about eighty years ago, when the south-western 
enclosure wall round Uraniborg was broken through, in 
order to build a schoolhouse there. The Swedish antiquary 
Sjoborg visited the island in 18 14, but was chiefly inte- 
rested in the various slight antiquities from long before 
Tycho's time.^ But in 1823 and 1824 the clergyman of 
Hveen, Ekdahl, examined the interesting spots carefully. 
At Uraniborg he found the deep well, which was easily 
cleaned out, and still gives excellent water; also some 
water-taps and pipes from the hydraulic works which had 
sent the water to various parts of the house. Parts of the 
foundation walls and some slight remains of the laboratory 
were also unearthed. At Stjerneborg Ekdahl was more 
successful, and found distinct traces of all the crypts, and 
one of them (F. on the plan, p. 106) in perfect preserva- 
tion, with all the circular steps, and the low column in the 
middle, on which the large quadrant had formerly been, 
fixed. The only ornament or inscription found was the 
stone with the words also put on Tycho's tomb : " Nee 

' Yoyage d'Uranihoiirg parJU. Picard, Paris, 16S0 ; also in Seceuil d' Obser- 
vations, 1693, and in Picard's Ouvrages de Mathcmatiques, Amsterdam, 1 736. 
This little book is remarkable for containing tiie first distinct description of 
the phenomena of aberration and nutation. 

" Philos. Trans., xxii. p. 692, xxiii. p. 1407. Hell's Reise nach Wardoe 
itnd seine Beohachtimg des Venus- Durchganges, Wien, 1835, p. 161. Hell and 
Sainovics were atHveen in May 1770 on their return journey from Wardohus. 
They give a rude diagram showing the ramparts, with a hole filled with water 
in the middle ; also the site of Stjerneborg, the cellar found in 1747 (errone- 
ously placed), and a hut where some Swedes had observed the transit of 

^ Sjoborg, Samlingar for Nordens Fornalskare, iii., Stockholm, 1830, 4to, 
p. 71 e* seq. 


fasces nee opes, sola artis scepfcra perennant ; " so strikingly 
illustrated by the state of Tycho's works on earth and his 
labours in science.^ Low stone walls form oval enclosures 
round the sites of Uraniborg and Stjerneborg, but other- 
wise the scanty remains of the buildings are quite unpro- 
tected, and will soon entirely disappear, being exposed to 
wind and weather. It is therefore well that they have been 
carefully described, first by the Danish poet, J. L. Heiberg, 
in 1845,^ and by the distinguished astronomer D' Arrest in 
1868,^ both enthusiastic lovers of the memory of Tycho 

' " Pornlemningar at Tycho Brahes Stjerneborg ooh Uranienborg p& On 
Hv4n, uptackte Sren 1S23 och 1824," Stockholm, 1824, 8vo. The inscription 
from the paper-mill given herein agrees with that of Danske Magaiin. See 
above, p. 186. 

^ Urania, Aarbog for 1846. Af J. L. Heiberg, Copenhagen, 1846 (also in 
his Prosaiske Skriftcr, vol. ix.), with fourteen plates, giving views of the island. 
On the 2ist June 1846 a great festival in honour of the tercentenary of Tycho 
Erahe's birth was held at Hveen, attended by many thousand Scandinavians. 

^ Astronomische NaeArichten, vol. Ixxii., No. 1718. The writer of the present 
work visited the island in 1874, at which time the ruins were still exactly in 
the state described by D'Arrest. 



1 564 Oct. 20 mane, distantia inter Saturnum at Jovem. 

1. Posito transversario in loco stato c[ui est partium 3500, reperi 
punctarum in transversario, a se invicem elongationem 1162, quibus 
juxta operationem proveniunt 398^ cui numero in tabula gnomonica 
competunt 18 gr. 21 m. distantia syderum quaesita. 

2. Collocato eodem in puncto 3700 pinnularum distantia reperiebatnr 
1233 quibus juxta operationem debentur 399|f- bisqve ex tabula respon- 
dent gradus ut antea, sed minuta numero 25 fere. Discrepat itaqve 
observatio in 3 [sic\ tantum circiter minutis, quod admodum parum est. 
Erat autem sine dubio vera distantia 18^ 22' infallibiliter. Stadius 
distantiam ponit 18^ 8, differentia o^ 14' parva (tantum erroris facit, 
amborum semidiameter additus o^ 8 ita 6). Qvam Carellus constituit 
1 5^ 20' diff. 3* 2' Magna., 

The above observations are calculated by the rule of Gemma Frisius 
(De Radio astronomico et geometrico liber, Antwerp, 1545, cap. 15): 
Multiplico igitur maximum tabulas numerum, nempe 1200 per pinnul- 
arum interstitium, producuntur autem . . . , atqve hunc numerum 

divido per transversarii locum. In the first observation = 

^ 3500 

398^1 ; Gemma's Tabula gnomonica O. Peurhachii then gives the required 

angle thus : — 

398 18' 20' 57" 

399 18° 23' 32" 

400 18° 26' 7" 


In the Danske Magazin, 4th Series, vol. ii. p. 32, the Rev. Dr. 
Rcirdara has communicated a list of Tycho Brahe's pupils, found on a 
loose sheet of paper (without heading or other description) in the Koyal 
Library of Copenhagen. The handwriting seems to be that of Johannes 

38 L 



Aurifaber or Hans Crol, who had charge of Tycho's ■workshop, and 
whose writing frequently occurs in the volumes of original observations 
{Danske Magazin, 4th Series, vol. ii. p. 327). The list must have 
been written in 1588 or 1589, as Odd Einarsen (No. 13 on the list) 
became Bishop of Skalholt in 1588, and Longomontanus, who is not 
mentioned, arrived in 1589. 

1. Petrus Jacobi.i 

2. N. Fionius.2 

Gellius Sascerides Hafniensis. 
Andreas Wiburgensis,agit nunc pastorum siue ecclesiastenWiburgi 

in Gutlandia.^ 
Jacobus Hegelius siue Hegelun, agit hypodidasculum in Selandia 

Sorae ; bene scribit et est bonus musicus, ingenij mercurialis. 
Seuerinus N., turbator, phantasta. 
Elias Olaj Cymber. 
M. Nicolaus Norwegianus, ]Drffioo diuini verbi Hafnie, in aroe 

. Eudolphus Groningensis, in primis non erat studiosus, 

creatus procuratione Tychonis in studiosuni Hafnie, vbi 

deposuit Bacchanten, fuit apud Tychonem per 3 annos.^ 
, Joannes Buck Cymber, natus non procul a CoUingo, in pago 

Nabul, fuit optimi ingenij, ocoisus iactu lapidis ab altero 

quodam studioso Hafnie. 
, Andreas Jacobi Lemwicensis Gutlandus, siue^^ 

Cymber, f ortasse alicubi pastor in Gutlandia. 
, Otto Wislandus Islandus, episcopus in Is- 

landia, est mediocris grammaticus aliasque 

non ignarus.* 
, Joannes Wardensis Cymber, sacellanus in 

quodam pago in Gutia.' 












Hi 9uno eodemque 
tempore accesse- 
runt, menstru- 
oque spacio vel 
vltra, petentes 
et obtinentes 

^ Peter Jaoobsen Flemlose. 

^ From the island of Fyen ; name evidently forgotten. 

3 His name occurs in the observations of February 1582 {Efist. Coil., p. 6); 
probably it was he who examined the pockets of Reymers (see above, p. 275). 

* Niels Lauridsen Arctander died i6i6 as Bishop of Viborg (Jutland). — 

^ Observed, among other things, comet 1585 (06s. Comet., p. 63), occurs in the 
diary in 1586 and 1588. 

« Odd Einarsen, Bishop of Skalholt in 1588. 

' Perhaps this is Joannes Bernsson, "unus ex meis familiaribus," by whom 
Tycho sent a letter to H. Bantzov in 1585. 

NOTES. 383 

21. David Joannis Sascerides, Gellij frater, fuit liio per semis.sem 


22. Jacobws N. Malmogiensis, egit in hac insula diaconum, et fuit 

studiosus, is primus literas obligationis dedit ad triennium, 
nunc est sacellanus Malmogise, vel eius loci in vicinia, degit 
tamen Malmogise, non fuit autem He diutius q^uam sesqui- 

23. Christiernus Joannis Eipensis,^ accessit eodem tempore quo 

antedictus Jacobus N. Malmogiensis disoessit, nempe anno 
1586 circa finem Aprilis, videlicet 27 Aprilis.^ Discedebat 
anno 90, 23 Aprilis.^ 

24. Petrus Eichterus Haderslebiensis, fuit hie fere per semi annum. 

25. luarus Hemmetensis Cymber, de pago Hemme in Cymbria, vbi 

pater'eius pastorem agit, fuit hie per semestre, fuit poetici 

26. Sebastianus, regise mensae alumnus, fuit Borussus, vertit Kbrum 

danicum in idioma germanicum, non dedit operam mathesi, 
fuit hie per mensem vnum vel alteram. 

27. Joannes Hamon Dekent, Anglus nobilis, fuit liio studiosus, fuit 

hie per quadrantem anni, et ingenij merourialis, musicus, et 
alias mediocriter eruditus.* 

28. Joannes Joannis Wensaliensis Cymber, fuit hie per sesquianum, 

erat astrictus autem ad 3 annos. 

29. Ego.^ 

30. M. Nicolaus CoUingensis. 

31. Martinus Ingelli Coronensis.' 

32. Christiernus N. de Ebenthod oppido Cymbrie, hue missus a 

Palcone Goye,^ fuit proximus qui post Christiernum Joannis 
Eipensem accessit, fuit . . .^ 

To supplement the above list I add the names of the other pupils or 
assistants, as far as their names are known, with references to places in 
this volume where further information about them is given. 

Paul Wittich. 
Longomontanus (1589-97). 

1 Afterwards Professor in the University ; born 1567, died 1642 as Bishop of 
Aalborg. He was at Hveen 1586-90, observed the comet of 1593 at Zerbst in 
Anhalt, and the solar eclipse of 1598 in Jutland [Hist. CceL, p. 819). 

2 Agrees with diary. 

3 Remark about departure added afterwards (Rordam). 

* Died 1629 as Bishop of Kibe in Jutland (Rordam). 

^ Probably Dekent should be de Kent. In the diary we read under 2nd Novem- 
ber 1587: "Hamon abiit." Could he have been John Hammond, afterwards 
physician to Henry, Prince of Wales ? 

* Probably Hans Crol (see above and p. 211), died 30th November 1591. 
^ i.e., from Landskrona. 

* Falk Gjoe, a friend and kinsman of Tycho, to whom the latter addressed a 
Latin poem printed at Uraniborg. 

' Paper worn at the corner ; a few words lost (Rordam). 

38 1 NOTES. 

Cort Axelsen of Bergen (Conradus Aslacus), at Hvecn 1590-93, 

afterwards Professor of Divinity at Copenhagen, edited Tycho'a 

Oration on Astrology in i6io. 
Jdh. Isaacsen Pont anus, for three years atHveen,' born at Elsinore 

of Dutch parents in 1571, some time Danish historiograplier, 

died in Holland 1639. 
Willem Janszoon Blaeu, p. 127. 

Franz Gansneb Tengnagel von Camp, pp. 242, 3or, &,c. 
Georg Ludwig Froben, p. 253. 
Claus Mule, pp. 240 and 283. 

At "VVandsbeck and in Bohemia Tycho was assisted by Johannes 
from Hamburg (p. 2S0) ; Joliannes Miiller ; Johannes Erikseu ; 
Melohior Joestelius ; Ambrosius Rhodius ; Matthias Seyffart ; 
Paul Jensen Colding ; and Simon Marius. 

7th DECEMBER 15S7. 

aUcittcn frcuitt(ic|tn gniciS mitt ivmnr(!^itng <iXki gucttc« atjcitt Bcfoi'V. (SMcr, 
(S()vit»eflEv, fvcmibttic^ct ticBev ©c^wagct »nb ticfoubct uoctratoctcu fvcunbt. 
5Rc6en Saiitfaguiig fur Mictfcttige cvjcigcte iiiottljatcn tail i^ bir fi'cimbttic^ei- 
U'otmciuuiig nit^t ucvt^attcn, ba(S ic^ bcin fc^ceiOcit l)aBc cutpfangcn »iib batimic 
citi ©ovic bc« !Duri^lcud)tigcti §oc^gi'I)ci'ncn Surficu »nb §cvvcn •&cr^og SStcidja 
5U ![)}cct)ct£(in'g an ®iv gcf^iiefienc bricff^, luovnup it^ evfa()vc, ba8 i()t fuv|lti(^c 
©luibe 6cget)tctt »cit mit giicbic£)(i(^ ju toiffcit, wctc^cc mciitc« ev(ic§ten« Son bcii 
Icibcit Prognosticatoribus Tobia S[)?t>((ev sub Andrea Rosa bent Scitl net)cr 
jutciift, it)nbent baf) bcv cine i()n biefem jutuiifftigen 88 3(;ai- ben {Rcgcntcn be« 
3ll)ar« Jovem »nb Venerem, bee anbec Saturnum Bnb Martem fe^et, baratjn 
fie nic^t adeine teinStI)ci[8 einig fcin, fonbern wie if)r ffiivfitic^e ®nabe fcljKibet, 
gaf)i- niibevwevtigcr nteinnng ()ii6en ; ban bcc einc ntaci^t ieibe benefices Planetas, 
bee anbct Bcibe maleficos (luie fie bic Astrologi nenncn) jum Sicgentcn im 
fetMgcn 3()av, inetct^e gar contrarie bcbeuttnng Iringett. Jpiecauff tan id; bir 
fceuubtid)cr meiniing nic^t fiergcn, ba« toicwoH ic^ in bic aftcotogifc^c ®ad;en, 
wclctic iebenttung ang bcm gefiirn ()ert)olen vinb iBeijfagungc tractiren, mid^ nit^t 
gerne eintacgc, biciueiK bavauff nic^t »t)i[( ju fiaioen i|l,@onbcrn allcin bie Astro- 
nomiam, wetc^c ben luunbertic^cu lauff beS ge(iitn« crforfc^ctt, in cinen geuiijen 
»nb rec^tmeffigen orbung ju tringcn mid) c^li(i^c 3f)ar Ijet 6emul)ct, ban baraljn 
tan burd) rc^tgefi^affene 3iiftrumenten iiac^ Ocomctrifcf) »nb Slrittimctifi'^ grunbt 
sub gcwi«t)cit bic eigeuttidje wartjcitt burc^ tangwivigeu ficijl sub arbeitt gefunbcu 
luetbeu, @c (jaljc id) boc^ nad) it)rer JuvPlii^er gnabcn bcgcritng beibe Prognos- 
tica, bie bu mitjr juf^idc|i, (bit ic^ bc^ niij^t, mie bu gcmcinctt ^aji, juscr 

I According to Pontoppidan, quoted in Bang's Samlinger, iL p. 279 (Woiatritz, 
i. p. 73). 

NOTES. 385 

gc'^att ]^a5e, ban id) iticmats ^fl'ccjc fcti^e practicen linbcr 51: faujfoit, iioi^ gu 
lefcn, ne bonas lioras male coUocem), burc^gcfctjen, bcit iimitjct, luovalju ciS 
I)ajftctt, bag ftc fo luibevtoei-tigt Judicia flcKcn, bavauS jit fiic^m, »nb Befiube, 
baS jtc ill ir^re Sftce^nimg gav i.nitcrf(^cibtic^c fundament gcbvauc^t tjnim ; ban 
bcv cinf, ncmtic^ Mollerns, Bawctt fcin Calculation aiif bcS Ijcdjcvfarncn 
Copernici vec^nung, bcr anbcr, Eosa, aiijf bie altc buvi^ btS JlcnigS Alplionsi 
in ^ii>anicn litcralitct gcniac^tc iSaictn, bie man barumB bie SltV>t)en|inifc6e 
neniictt. §iraup tomtit cS, iai bcv cine ben onfang bc3 3tior« in aequinoctio 
verno fc^ct oBm 10 tag 3)favlii Bc^ 9Jcun u'^t iiac^ ntittagc, bet anbcr aipn 
felBigen tag, aBev vmh 2 ©tnnben nae^ bcr sovgetjenbe SDJittcrna^t, bof atfo 
jtoifc^cn Bcibe itjre vc^nung fi^ict 19 gan^e ©tunben scvrauffcn, in wetc^cn ber 
^immcl ftc^ gar (jit tcrcnbcrn t^ntt, inib fan gar cin anbcr Sljirotcgift^ Judi- 
cium bavanf faffcn, cBcnfcirct als ircn bar cin gan^cg 3I)ar cbcr ■aei) fflctjr 
jlijircficn U'c'^rc : Sag barnmB nic^t jn uorwnnbcrn ift, bag biefe Bcibe Astrologi 
in domino Anni nic^t sBcvcin fitmmen, Weil fte ben anp ber Figura Caeli 
introitus Solis in Arietem, Iran ba^ liorBenicrtc aeqvinoctium vemum 
gcf(6i(^t, ^iflcgcn I)crBptcn. SBicwct eg au^ tic^ttic^ gcfdn'tin fan, bag hjan itc 
f(^on gleic^mcifigc SaBcIn »nb rc^nnngcn scCgctcn, tag lie gtci^wcK in Dominis 
Anni iinb it)ren gan^en ttciJTagnngcn gar wibcru'cvttge ntcinnngen fonncn fiitJ 
geBcn, bag baraug tciditlicS jn j)rcBircn ifl, baf Iran man Ijnnbcrtt bcr ^Ptognc;: 
ftictcn tiffct, fc Bcfiubett iic^ bcc^ gaBr fcltcn, bog ciner mitt bem anbern conccrbirett, 
ban fte Barren nitftt a.[k onf gtctdifcnnige grunbt t6n tr)ren Judiciis »nb BaBcn 
»ntt)crfc^cibli(^c process imb atjntcitnngen. (Jg fcin onc^ biffc Sljlrotogifc^e 
tociffagungcn irie ein cothurnus, ben man fan anjf cin jcbcr Sctn jicBcn, grog 
»nb Itein, >rie man iritt, barnmB icB ant^ nicmatg barscn ettirag <Scnbcrti(f>g 
gcl)atten IjaBe. Sag td^ aBcr ^ong. aifaf. meincn ©nebigflcn |icrrcn fBarlic^ ein 
fotcBeg Slfirclcgif^ Prognosticon untBertenigtic6 jnilcfte, mug ic^ in bem nacB 
iBre !Kai). Befed »nb nnttcn t^nn, toicwptl i^ fcIBjl nic6t sitt baranf ^atte t>nb 
nic^t gemc mitt fott^cn jtrcifcIBafftigen praedictionibns smBgcBc, barin man bie 
cigcnttli^c irarljeitt nit^t burc^an? crfcrfcBcn mag, n>ic fonft in Geometria Bnb 
Arithmetica, bovaujf bie Astronomia burc^ Ijutjf ber steifTigcn observation 
itjm lanff beg Itimclg geBatret irirtt. Senncc^ btctrcin iBr gnrftti^e ®nabc 
gncbigttc^ Begcrtt son mir ju totffen, »et(^cn »on ben Bcibcn ic^ BcifcKig fo*i, irag 
ben dominis Anni atfo toiberlocrtiger tocif rcn iljncn gefleffct ttjntt oBntangen, 
So Ian i^ ^icrauff ni^t anbcrg fagen, ban bag itjrcr Bcibcn rec&nung Bnb 
indicium gcBtt a.\\% ein ijormcintcn snri^tigcn grunbt ; ban trcbcr bie Slt^Bctti 
ftnifc^en nccB bie Scljcrnianifi^en SaBcIu, lucti^en ftc fc(gcn, gcBcn ben jitficn 
taiiff bcr ©ouuen. hjie cr aBn fid^ fctBil axa §immct gcfcfcicBtt, sub ijl Ijicrinne 
fcin gcrtnge rutcrfd&cibt, nne au§ mciner ctgcncn Restitution »ub Botncterung in 
Sfte(^nung beg tanfg bcr ©onucu ju feljen ijl, ttclc^e xi) auf c^ti^e BorgcBcnbc 
SBaten bnrt^ grcge unb rc^tmcjfige 3nfivnmentcn augenf(^einti^ Bom §imct 
felBfl t)cr oB bur^ flcigigc observation Bnb iBarncmungeu gcuDmen BaBe, ang 
Iretc^en ftc^ Bcfinbet, bag b^:? ,3Barg Slnfang in aequinoctio verno, baraug bie 
Astrologi i^re ortBcit ncljmcn, gcf^ii^t oBm 10 tag SDJartii 8f flnnbe nac^ bcr 
Bcrtgcn aRitternait, wAifS Bci) 7 fiunbcn fpcbcr ijl, a(g Slnbrcag {Rcfa gcfc^t Bat, 
unb 12 fiunbcn frucr, atg iicBiag aWcKcrug mcinett, bavaug ben Btjit cin aitbcvc 


386 NOTES. 

constitution Ui ^m(U jur 3>ntt itg aequinootii einfcttt, aU eiit je|ttc§er scrt 
i^nen gefunbcn '^at, iroraujf ou^ ein onber jjtttieiH fotgctt »nb aud^ inot anbcre 
domini Anni, tote fte e« neniien, (barauf bo^ nic§t utiit ju :^o[en ill), mogcn 
gcfe^t toei'ben. SfEaS aber meine meinung fet) a'^ntangcnbe Slflro(ogif(^c gi^ung 
sber big lunfftige 88 3^or, 'ijait id^ Mim%l. SKaij. meinen gnebig^en ^crren i^n 
einen gefc^riebcncn Prognostick sntertenigtii^ ouffgejeignctt, iticl^g i^ ouc^ i^re 
gurjilic^e ®nobc gcrne tootte »ntertcnigtii^ mifteilen, aber ii^ :^ob leine »bectgc 
Qxtmpiax barson, toon i:^r guvjitii^e ®nabe laffet bet) itir SKa^. barumb a^nlan= 
gen, toitb i^r Suvji. ®na. toot ein abfc^rip bar son betomen. 3i^ bin barinne 
gen^tic§ nic^t ber meinung, baf foli^e ga^r grope Borenberunge in biefen negji; 
funftigen 3§ar Bort;anben fein, afe bie Astrologi aup e^tid^en alien reimen, bie 
fte ben Eegiomontano gutneJTen, furgeben, ban i^ befinbc im Eonjiitution beg 
^imeU feine ©onbertii^e »rfac^en barju, fonbern ac^te, bag big tepige 3^ar 
toirb ben sorgc^enben gtei^mejig fein »nb in gimtic§en gutcn toefen in alien 
©ac§en ftc^ ergeigcn, ateine too juuor fvieg »nb Bneinig!eitt aujfertoectt iji, bar 
mcc^te eg toot ettaag toeitter einrcifen. SSnb fan i^r gurjili^e gnobe nteine 
meinung Bom Sl|ivotogifc§en judicio Bber bag gan|e S^at auf Borbentetten 
Prognostico, toetc^g i6) siting. iKaS}. meinen gnebigjien ^crren Bntertenigti^ 
I)abe jugejietlt, toeitter erfa:§ren. !Dig J)abe ic^ aujf bein gutttoilligeg fi^reiben 
Bnb beger nic^t tootlen Bnt^^crtaffen ju anttoorten. IBittc gar beinpti^, bu 
tootteji Bnbcfc^toert fein »nb mitt erjier getegen^eitt ifjx gurilti(|c @nabc tiierauff 
meine anttoort Bnb meinunge Bntertenigtic^en Bon meinetttoegen ju BorjJe^n 
geben. SEorin i(^ fonji i'^re 5ur|itii^e gnaben ju toitten Bnb gefatten fein 
tan, bin i^ aljeitt mitt o((er beinjitic^feitt sntertenigti^ erbottig. 

[The remainder of the letter is about paper for Tycho's books ; see 
above, p. 163, footnote.] 


[Written in the volume of Observations for 1600-1601. Compare Oissi-vationes 
Hassiac(B, pvMicante W. Snellio, Lugd. Bat., i5i8, p. 83.] 

Die 13 Octobris Tycho Brabe Dominum a Mincowitz ad coenam 
Illustriss. Domini a Eosenbercb comitatus, retenta praeter morem 
urina consedit. Cum paulo largius biberetur sentiretque vesicae ten- 
sionem valetudinem civilitati posthabuit. Domum reversus urinam 
reddere amplius baud potuit. 

Erat bujus morbi initio ^ in opposito \ , & □'" ,5 in 0, & (j eodem 
loco quern sibi Tyobo orientem gradum constituerat. 

Transactis quinque diebus insomnibus, cum gravissimo cruciatu vix 
tandem urina processit, & nibilominus impedita. Insomnia sequeban- 
tur perpetua, febris interna & paulatim delirium, ratione victus, h. qua 
prohiberi non poterat, malum exasperante. Ita die 24 Octobris cum 
delirium aliquot horis remisisset, victa natura inter consolationes, preces 
& suorum lachrymas placidissime expiravit. 



Ab hoc itaque tempore series otservationum Coelestium interrupta 
est, fliiisque inipositus 38 annorum observationibus. 

Nocte, quam ultimam habuit, per delirium, quo omnia suavissima 
fuere, creberrime liaec verba iteravit, quasi qui carmen texit. 
Nefrustra vixisse videar. 

Quem procul dubio ceu colophonem operibus suis addere, eaque his 
verbis Posteritatis memorise c& usibus dedicare voluit. 


The following table gives the places for 1586 (anno 1585 com- 
plete) of Tycho's nine standard stars {Progymn.,'p. 204), and their posi- 
tions for the same epoch, computed from those of Bradley for 1755, 
with the proper motions of Auwers {Neue Reduction der Bradley'schea 
Beolachtungen, vol. ii.). 

a Arietis . . 

Observed AB. 

Observed Dec. 

Computed AR. 

Computed Dec. 

26° 0' 30" 

+ 21° 28' 30" 

26° 0' 44."7 

+ 2i°27'33".o 

a. Tauri . . 

63 3 45 

+ 15 36 IS 

63 4 11.2 

+ 15 35 35-6 

f/. Gerainorum 

89 29 10 

4-22 38 30 

90 28 41.0 

+ 22 37 48.5 

/3 Geminorum 

109 58 

+ 28 57 45 

109 S7 47-9 

+ 28 s6 19-1 

Leonis . . 

146 32 45 

+ 13 57 45 

146 33 19.7 

+ 13 56 56-9 

a Virginis . 

195 52 10 

- 8 56 20 

195 S2 36.4 

- 8 58 22.0 

5 Ophiuchi . 

238 II 20 

- 2 33 IS 

238 II 9.8 

- 2 33 21.5 

a Aquilse . . 

292 37 20 

+ 7 51 20 

292 38 36.2 

+ 7 SO 35-8 

a Pegasl . . 

341 2 30 

+ 13 40 

341 3 1-3 

+ 12 59 47-1 

The differences between Bradley and Tyoho are shown in the next 
table. The effect of refraction (which Tycho thought insensible above 
Zen. Dist. 70° or Declination- 14° for Uraniborg), is seen at a glance, 
and I have therefore in the last column given the difference of declina- 
tion corrected for mean refraction. 

Beadlby minus Tvoho. 

A a 

A a COS S 



a Arietis 

+ 14"-7 

+ i3"-7 



a Tauri 




+ 9.6 

11 Geminorum 




- 3-6 

/3 Geminorum 

- I2.r 

- 10.6 



a Leonis 

+ 34-7 

+ 33-7 


+ 4-4 

a "Virginis 

+ 26.4 

+ 26.1 

- 122.0 

-1- 0.6 

5 Ophiuchi . 


- 10.2 

- 6.S 


a Aquite 


+ 75-4 


+ 19.5 

a Pegasi 

+ 31-3 

+ 30-4 


- 0.1 



From the third and fifth columns we find the probable errors of 
Tycho's standard right ascensions = + 24".!, and of his standard declina- 
tions = + 25".9. Of course the accuracy of most of his star-places must 
be much less, as they were neither as often nor as carefully determined 
as those of the standard stars, and were vitiated not only by refraction, 
but also by aberration and niitation. See above, pp. 351 and 353. 


In order to remove any doubt which the reader might have as to the 
correctness of the opinion set forth above on p. 360, that the azimuth 
error of 15' detected in some of the instruments in November 1586 does 
not prove aU Tycho's instruments to have been erroneously placed 
during all the years previotis to 1586, I have tested the matter by 
calculation. Azimuths were never very extensively observed at Hveen, 
and the only series of observations sufficient for my purpose was that 
made in the beginning of 1582, when a number of altitudes and azi- 
muths of bright stars were measured. Many of these were taken too 
near the meridian to be of any use in this case, but there are many 
observations made in the prime vertical, by which a great error in the 
assumed zero of ' the azimuth circle would easily be detected. I have 
made use of all the observations taken in or near the prime vertical 
during March 1582 (except of a few which were vitiated by some great 
error of copying, observing, or in the identification of the star), and of 
one observation of a Tauri in azimuth 69° on February 25.1 The fol- 
lowing mean declinations for 1 582 were computed from Auwers' Bradley 
the reductions to apparent declinations for ist March being appended : — 

a Tauri 

• +15° 35' 0" 

+ 4' 

/3 Heroulis 

-1- 22 27 so 

- 20 

K Ophiuohi 

+ 10 5 45 

- 17 

a Herculis 

+ 14 56 20 

- 12 

a Ophiuchi 

-1- 12 56 14 

- 18 

a Lyrse 

4-38 26 50 

- 19 

/3 Cygni 

4-27 8 32 

- 10 

t Cygni 

+ 50 52 36 

- 18 

7 Cygni 

+ 38 57 48 

- 12 

Assuming the observed altitudes to be correct, the azimuth cor- 
responding to each altitude was computed by the formula 

„„„ . sin d) sin h — sin S 

cos A = ^ 

cos <f) cos h 

1 Hutoria Ccelestis, p. 34 et seq. My copy of this work formerly belonged to 
Professor Schjellerup of Copenhagen, who corrected a great many of the errors 
in the observations of fixed stars (by comparing with Bartholin's copy) including 
fortunately those of 1582. 

NOTES. 389 

ill which" 8 is the apparent declination, h the observed altitude corrected 
for refraction, and (f) the latitude of Uraniborg, 55° 54' 26". The com- 
puted and observed azimuths were found to be in excellent agreement, 
the differences only in nine cases exceeding 3'. Thirty-six observations 
of nine stars gave the correction to the observed azimuths (counted from 
0° to 360° from south through west) = -o'.4 -I- o'.3o. Of course this 
result is affected by the errors of observation in the altitudes, but at 
any rate it shows most conclusively that Tycho Brahe's azimuth circles 
were adjusted with the same care which we have seen he bestowed on 
his other instruments ; and the assertion that Tycho from 1579 to 1586 
had all his instruments set 15' wrong in azimuth is hereby proved to 
have been utterly without foundation. 


[From P. D. Huetii Commentarius de rebus ad eum, pertinentibus, Amsterdam, 
1718, i2mo. After describing the great celestial globe, the author relates how 
he started for Hveen, with only one companion, on the 26th May 1652, and after 
telling the story about the origin of the name of Insula Scarlatina and praising the 
hospitable reception by the Lutheran clergyman, he continues on p. 86.] 

Humaniter ergo excepti, postqviam paululum interquievimus, multa 
ab hospite nostro, aliisque adstantibus Huense incolis peroontatus sum 
de Tychone, deque Vraniburgica arce, cujus visendse gratia i'stuc venis- 
sem : quodque mirere, incognita sibi esse hsec nomina uno ore professi 
sunt omnes, nee q\iicquam se de iis accepisse. At cum virum quemdam 
valde senem sviperesse rescivissem in insula, misi qui eum ad me addu- 
cerent. Eogatus ille a me numquid de Tychone Braheo inaudisset 
aliquando, deque condita olim ab eo istic arce quam Vraniburgi nomine 
decorasset, & per annos unum & viginti incoluisset ; se vero respondit 
non Tychonem modo & Vraniburgum nosse, sed & in Tychonis 
famulatu fuisse per aliquod tempus, & operam quoque suam ad hano 
exstruendam aroem contulisse. Tychonem autem referebat hominem 
fuisse violentum, impotentem, iracundum, famulos & villicos male 
multantem, ebriosum quoque et mulierosum ; cum uxorem duxisset 
ex infima natalis villie suse Knudstrupii plebe rustica, ex qua liberos 
niultos suscepisset, atque hac affinitate, velut sibi probrosa, magnopere 
offensam fuisse illustrem Braheorura gentem. Turn subjecit bonus ille 
vir, si istuc venissem spectandi Vraniburgi causa, irritum me laborem 
suscepisse, quippe solo Kquata omnia, vixque superesse parietinarum 
vestigia. Cujus rei causas cum ab eo, & jam ante Hafnise a viris doctis 
exquisivissem, varias ac plane discrepantes commemorabant. Hi enim 
Tychonem ipsum, e Dania excedentem opus suum diruisse dicebant, 
cum satis tamen constet res suas Huenicas & Vraniburgicas colono & 
famulis aliquot procurandas reliquisse ; quippe fundi hujus fructus in 
totum vitae tempus fuisse ei a Frederioo Eege concessos. Erant qui 
dicerent hostiles Suecorum copias pervasisse in insulam, stragemque 

390 NOTES. 

banc edidisse ; quod non ignorasset profecto vetus ille Huense incola 
qui ad turbidas Freti Sundici tempestates & rapidissimos ventos rei 
causam referebat ; quibus facile conoussfe fuerant sedes leviter materi- 
atse : cum prsesertim de tuendis sartis tectis Astronomicae domus parum 
omnino laborarent aulici viri, quibus clientelce jure, post Tycbonem, 
Regis beneficio obtigerat. 


[Compiled by means of the list in Bugge's Observationes astronomical {1784), 
compared with the library catalogues and the Tolnmes themselves, with the kind 
assistance of Dr. C. Bruun, chief librarian. The MSS. form part of the so-called 
Old Royal collections, Qamle Kongelige Samlmger, the numbers of which are 
added in brackets.] 

I. Original Observations. 

Observationes astronomicas a solstitio Hiberno anni 1577 ad annum 
1582 ; maxima ex parte autographum, 4to, 197 ff. [No. 1825, 4to.] 

Observationes ab anno 1582 usque ad annum 1587 ; ex parte autogr. 
In folio, 500 ff. [No. 311, fol.] 

Observationes astronomicse ab anno 1587 ad 1590 usque ad Jan. 26. 
In folio, 344 ff. [No. 312, foL] 

Observationes astronomicae ab anno 1590 usque ad a. 1595. In folio, 
340 ff. [No. 313 fob] 

Observationes planetarum super annum 1595 institutse. In folio, 173 
ff. [No. 314 foL] 

Observationes cometse anni 1590, nee non cometae 1596 apparentis. 
[No. 315 fob] 

Observationes planetarum et flxarum anno 1596 et 1597 ad d. 15 Mart. ; 
narratio de occasione interruptarum observationum et discessus 
mei ; obs. continuatae Wandesburgi a 20 Oct. 1 597. Adjectus est 
in fine catalogus fixarum ad annum 1588 completum.' In folio, 
151 ff [No. 316 fob] 

Liber observationum Tyohonis Brabe pro 1 598 Wandesburgi, nee non 
observationes astronomicaa factse Wittebergae a solstitio hyberno 
praecedente annum 1599, et varise alias in Arce Benatica factse 
eodera anno. In folio, 167 ff. [No. 317 fob] 

Observationes astronomicae annorum 1600 et 1601 in Arce Caesarea 
regni Bohemici Benatica & Pragae babitae per instrumenta Tychonis 
Brabe. Accedunt observationes, quas anno 1600 factas Keplerus e 
Stiria Tychoni misit. In folio, 171 ff. [No. 318 fob] 

Observationes [autograpbac] cometarum a. 1577 et a. 1580 et observa- 

' The catalogue has columns for RA, Deol, Long., Lat., and Magn., but very 
little has been filled in. 

NOTES. 391 

tiones [apograpliEe] cometarum qui annis 1582, 1585, 1590, 1593 et 
1596 apparuenmt.i ^^q_ [No. 1826, 4to.] 

2. Copies of Ohservations, Miscellaneous Computations, dv. 

Observationes Lipsise annis 1563-65, Eostochii 1568, Augusts Vinde- 
licomm 1569-70, Heridsvadi, Hafnite et in insula Hvena 1573-81 
factae, preemissis excerptis ex observationibus G. Frisii et Regio- 
montani.2 4to, 280 S. modern binding. [No. 1824. 4to.] 

Observationes septem Cometarum 1577-96. 4to. [No. 1827, 4to.] 

Fasciculus continens theoriam Solis per observationes Lunse ad ilium 
et fixas, Lunaria 1582, 1586, 1590, 1593. Observationes Veneris 
1586, Jovis 1593, Saturni 1590. 4to, 145 fob, modern binding. 
[No. 1830, 4to.] 

Computatio observationum Solis, Lunse et planetarum 1599 et 1600 & 
comparatio cum tabulis. 4to. [No. 1829, 4to.] 

Fasciculus observationvim Brahei, variorum annorum ex quibus 1590 
1598, 1599 et 1600 expressi sunt. Addita sunt excerpta ex 
quodam libro MSo ex collegio Pragensi a M. Bacchatio Tychon, 
communicata. 4to, 478 ff., modern binding. [No. 1828, 4to.] ' 

Tyclionis Brahei stellarum octavi orbis inerrantium accurata resti- 
tutio. [No. 306, fol, presentation copy to King Christian IV.] 

Idem liber [No. 307, fol., presented to Johannes Adolph, Bishop of 

Observationes qusedam astronomicee habitse 1 5 89 per Quadrant em orichal- 
cicum Tychonis Brahe, divisionum satis capacem, in diversis locis 
Danife ad eruendas eorum Poll elevationes. 4to. [No. 183 1, 4to, by 
Elias Olai, see above p. 123, footnote.] 

CoUectio observationum Tychonis Brahei in L. Baretti Historia Coel- 
esti omissarum per Erasmum Bartholinum. In Folio.* [No. 3 lo, 
fol., includes the observations of comets.] 

1 The original observations of the comets of 1582 and 1585 are in the folio 
volume for 1582-86. 

2 These excerpts fill two leaves. There are also some notes on the comets after 
the year 1500, and among the observations are astrological notes and comparisons 
■with ephemerides. In several places the observations have afterwards been 
verified or reduced by means of the great globe, e.g., under 1570, 5th March, 
where there is written in the margin : " Manu Christiani Severini Longomontani 
recentius seriptum ; " and on the next page : "Manu Tychonis, sed recentins, scrip- 
turn." This volume has often been quoted above in Chapters ii. to v. It is the 
volume referred to in Connaissance des Temps for 1820, p. 386. 

' I have not seen this volume myself. Dr. Bruun informs me that it has 
originally consisted of two bundles, the first begins "Observationes 3 Die 27 
Februarii," and consists of 260 leaves ; the second is headed " Astronomicse Obser- 
vationes anni 1598," and consists of 218 leaves. It is written in the same hand 
as No. 1829, 4to. Bugge's No. 6 (p. xvii. last two lines) could not be identified, 
and the last and third last items on Bartholin's list (Werlaufl's Historiske Efter- 
ntninger om det store kgl. Bihliothek, 1844, p. 54) are not now at the Royal 
Library. One of these is an 8vo volume of observations, 1563-74 (originals?), 
which probably was lost in Paris, or on the way back in 1707. 

* Bartholia's corrected copy of Barrettus is mentioned above p. 374. 

392 NOTES. 

About tlie copies of observations ia the Hofbibliothek at Vienna and 
at the Paris Observatory, see above, p. 372 et seq. The three astro- 
logical MSS. [No. 1820-21, 1822, 1823," 4to] are described above, p. 145 


The titles of Tycho Brahe's own publications (including the posthu- 
mous Oratio de disciplinis mathematicis and the observations published 
by Snellius and in the Historia Ccelestis) have already been given in 
full in the text. The following is a complete chronological catalogue of 
books and memoirs containing biographical details or investigations of 
Tycho's scientific work, omitting popular accounts in which nothing new 

Tychonis Brahei, Equitis Dani, Astronomorum Coryphaei, Vita. 
Authore Petro Gassendo, Regio Matheseos Professore. Aocessit 
Nicolai Copernioi, G. Peurbachii & J. Begiomontani, Astrono- 
morum celebrium Vita. Editio secunda, auctior & correotior. 
Hagse Comitum MDCLV. 4to, Ix. + 384 pp. [of which 287 pp. 
about Tycho Brahe ; ist edition published in 1654 ; pagination of 
the two editions agree. About Gassendi's sources, see his letters 
in his Opera, vol. vi. pp. 518-527]. 
Encomion Regni Daniae. Det er Danmarckes Riges Lof. Af J. L. 
"Wolf. Kjbbenhavn, 1654. 4to [pp. 525-529 about the island of 
Le Grand Atlas ou cosmographie Blaviane, en laquelle est exactment 
descritte la terre, la mer et le ciel. A Amsterdam, 1663, fol. 
[Large map of Hveen, with letterpress in vol. i. p. 61 et seq., and 
figures of Tycho's instruments.] 
P. J. Resenii Inscriptiones Hafnienses, Stellaeburgenses, Uranibur- 
genses, &c. Hafniee, 1668. 4to [p. ^loet seq. are given a number 
of inscriptions at Uraniborg and Stjerneborg, and a letter from 
Tycho Brahe to Peucer, all of which are reprinted by Weistritz 
in his first volume]. 
Voyage d'Uranibourg ou Observations astronomiques faites en Dane- 
marck, par M. Picard. Paris, 1681, fol. [Reprinted in the 
Recueil des observations faites en plusieurs voyages, Paris, 
1693, fol. ; and in Picard's Ouvrages de mathematiques, Amster- 
dam, 1736, 4to, pp. 61-99.] 
Epistolse ad Joannem Kepplerum scriptse. Ed. M. G. Hanschius. 
Lipsiae, 1718, fol. [On pp. 102 et seq. letters from Tycho, see 
above, p. 290 et seq."] 
Pet. Dan. Huetii, Episcopi Abrincensis, Commentarius de rebus ad 
eum pertinentibus. Amstelodami, 1719. i2mo [pp. 81-89 about 
Tycho Brahe and Hveen]. 
Tychonis Brahe relatio de statu suo post discessum ex patria in Ger- 

NOTES. 393 

maniam et Bohemiam ad M. Andr. Velleium ex manuscripto 
edita a G. B. Casseburg. Jenae, 1730. 4to, 23 pp. [The same 
is more correctly printed in Danische Bibliothec oder Sammlung 
von alten mid neiien gelehrten Sachen aus Danemarck, III. 
Stuck. Copenhagen, 1740. 8vo, p. 177 et seq.] 

Singularia historico-literaria Lusatica, oder historische und gelehrte 
MerckwUrdigkeiten derer beyden Marggrafthlimer Ober- und 
Nieder-Lausitz, 27"'* Sammlung, 1743. 8vo [contains, p. 177 et 
seq., four letters from Tycho to Scultetus, see above, p. 133]. 

Cimbria Literata. A Job. MoUero. Hafnise, 1744. Tom. ii., fol. 
[contains on pp. 103-118 a biography of Tycho Brahe, with some 
interesting details]. 

Samling af adskillige nyttige og opbyggelige Materier, saa vel gamle 
somnye. Kjobenhavn, 1745. 8vo, v.-vii. Stykke [vol. ii.] ; Den 
store vidtberomte Danske Astronomus . . . Tyge Brahe . . . 
Hans Liv og Endeligt. [By Mag. Malthe and the editor, 0. 
Bang, fills about 183 pp., chieiiy founded on Gassendi, but also 
containing a few new details]. 

Portraits historiqnes des hommes illnstres de Danemark. Par T. 
de Hofman. Sixifeme Partie. Copenhague, 1746. 4to [pp. 2-30 
life of Tycho Brahe, some new documents]. 

Danske Magazin, indeholdende allehaande Suiaa-Stykker og Anniterk- 
ninger til Historiens og Sprogets Oplysning. Andet Bind. 
Kjobenhavn, 1746. 4to. [Nos. 18 to 24, pp. 161-372, "Eare og 
utrykte Efterretninger om Tyge Brahe," by Jacob Langebek. 
In vol. iii., 1747, there is an account of Tycho's sister Sophia, pp. 
12-32 and 43-53, in which occurs the only known Danish poem 
by Tycho Brahe. The engravings in vol. ii. are borrowed from 
Hofman's Portraits.] 

Lebensbeschreibung des beriihmten und gelehrten Danischen Stern- 
sehers, Tycho von Brahe, aus der Danischen Spraohe in die 
Deutsche ubersetzt von Philander von der Weistritz. Kopen- 
hagen und Leipzig, 1756. 2 vols. 8vo. [Vol. i. is a translation of 
the biography in Bang's Samling, vol. ii. of the papers in Danske 
Magazin, vol. ii. ; the Danish original mentioned in Houzeau 
and Lancaster's Bibliographie, vol. ii., Ko. 6193, never existed. 
The portrait is borrowed from Hofman. The translator's name 
was C. G. Mengel.] 

Observations de Mars faites en 1593 par T. B., tiroes des manu- 
scrits par J. de Lalande. M^nioires de I'Acad. des sc. de Paris, 


Observations de Saturne et de Jupiter en 1593 par Tycho. Ihid, 
1763. [See above, p. 375.] 

Om Forskiellen imellem Tycho Brahes og Picards Meridian af 
Uraniborg. Ved [J. S.] Augustin. Skrifter, som udi det Kgl- 
Videnskabernes Selskab ere fremlagde og nu til Trykken befor- 
drede. XIL Bind. Kjobenhavn, 1779. 4to, pp. 191-216. 

Histoire de I'Astronomie moderne. Par M. Bailly. Tome i. Paris, 

394 NOTES. 

1779. 4to [pp. 377-389, 398-424 contain an account of Tycho'a 
scientific work]. 

Samraenligning mellem de 1672 af Hr. Picard og de nyere i Skaane 
giorte Observationer og Opmaalinger for at bestemme de tre 
Punkters, Uraniborgs, Kundetaarns og Lund's Observatoriers 
Situation. Af C. C. Lous. Nye Samling af det kgl. Danske 
Videnskabernes Selskabs Skrifter. 1,1781. 4to, pp. 142-155. 

Observationes astronomicae annis 1781, 1782, & 1783 institutae in 
observatorio Regio Hafniensi, auctore Thoma Bugge. Haunia, 
1784. 4to [pp. xiii.-xix. about Tycho's MS. observations]. 

De meritis Tycbonis Brahe in Astronomiam Mecbanicam. 0. Schil- 
ling et A. P. "Weller. Upsaliae, 1792. 4to, 13 pp. [Merely short 
descriptions of Tycho's instruments, and a plate with twelve 
small figures of them.] 

Geschichte der Mathematik. Von A. G. Kastner. Zweiter Band. 
Gijttingeu, 1797. 8vo [pp. 377-416 life of Tycho, pp. 613-660 
reviews of his books ; compare vol. iii. p. 469]. 

Histoire des Mathematiques par J. P. Montucla. 2™ edition. 1798. 
Tome i. 4to [pp. 653-674 about Tycho and his scientific work]. 

Geographisohe Lange und Breite von Benatek wo Tycho Brahe vor 203 
Jahren beobachtet hat . . . Von Aloys David. ■ Abhandlungen 
der KrJnigL Bohm. Gesellschaft der Wissenschafteii. Prag, 1802. 
[R&ume in Zach's Monatliche Correspondenz, vi., 1802, p. 468 
et seg.] 

Trigonometrische Vermessnngen zur Verbindung der K. Prager 
Stemwarte mit dem Loronzberg, und zur Bestimmung der 
geogr. Breite und Lange des Ortes auf dem Hradschin, wo 
'J'ycho Brahe beobachtet. Abhandlungen, &c. Prag, 1805. 
[Resume in Monatl. Corr., xii. p. 248]. 

Meridienne d'Uranibourg. Par M. Delambre. Connaissance des 
Temg pour I'an 1816. Paris, 1813, pp. 229-239. 

Extrait d'une lettre de M. Schumacher. Connaissance des Terns pour 
I'an 1820, pp. 385-387 [also about the meridian, compare Zach's 
Correspondence astronomique. Tome i., pp. 338 and 402]. 

Histoire de 1' Astronomic moderne par M. Delambre. Tome i. Paris, 
1821. 4to [pp. 148-260 reviews of Tycho's principal books]. 

Astronomifiche Nachrichten, No. 63 (Band iii.). [On an album be- 
longing to Tycho's son, and on 'a portrait of Tycho in water- 
colours (above, p. 263), by Biela.] 

Fornlemningar af Tycho Brahes Stjerneborg och Uraniborg pS, Oen 
Hv^n, aftackte 4ren 1823 och 1824. Stockholm, 1824. 8vo, 27 
pp., I plate. 

Samlingar for Nordens Fomalskare. Tredje Tomen. Af N. H. 
Sjbborg. Stockholm, 1830. 4to [pp. 71-83 about the state of 
Hveen in 1 814, with 2 plates]. 

Tyclio de Brahe als Homeopath. Von W. Olbers. Schumacher's 
Jahrbuch fiir 1836, pp. 98-100. 

Letter from Tycho Brahe to Thomas Savelle. A collection of letters 

NOTES. 395 

illustrative of the progress of science in Engliind . . . edited by 
J. 0. Halliwell. London, 1841. 8vo, pp. 32-33. 

Historiske Efterretninger om det store kongelige Bibliothek i Kjoben- 
havn. Ved E. 0. Werlauff. 2'"° Udgave. Kjbbenhavn, 1844. 
Bvo [52-60 and p. 411, about Tycho's MSS. at Copenhagen]. 

Observationes cometae anni 1585 Uraniburgi habitse a Tychone Brahe. 
Edidit H. C. Schumacher. Altonse, 1845. 4to, 32 pp., 2 plates. 

Urania, Aarbog for 1846, udgiven af J. L. Heiberg. Kjobenhavn. 
8vo [pp. 55-170, Hveen tilforn Danmarks Observatorium, on the 
state of the ruins at Hveen in 1845, with 14 plates]. 

T. B. Mikowec : T. Brahe ; ziwotopisni nastin, ku 300 lete pamatce 
jeho narozeni. Prag, 1847. 8vo [contains some information about 
the fate of Tycho's relations after his death]. 

Bestimmung der Babn des Cometen von 1585 nach den . . . Origi- 
nalbeobachtungen Tycho's. Astronomische Nachrichten, Band 
xxix. pp. 209-276. [By C. A. F. Petera, the most important 
investigation of the accuracy of Tycho's observations. About 
the orbits of the other comets, see above, p. 159 et seq."] 

De hellige tre Konger Kapel i Roskilde Domkirke. Af E. C. 
Werlauff. Kjobenhavn, 1849 [p. ly ei seq. about Tycho's pre- 

Historiske Efterretninger om Anders Sorensen Vedel. Af C. F. 
Wegener, 291 pp. fol. [Appendix to Den Danske Krijnike af 
A. S. Vedel, trykt paany. Kjobenhavn, 1851.] 

Danske Magazin. Tredie Esekke. 3'"° Bind [pp. 79-80, Letter 
from Tycho Brahe to Valkendorf of 1 598]. 4"'° Bind [pp. 263- 
264, Royal Letter to Tycho Brahe about the tenant Easmus 
Pedersen, of 17 November 1592]. 

Ueber den neuen Stern vom Jahre 1572. Von Prof. Argelander. 
Astronomische Nachrichten, vol. Ixii. pp. 273-278. 

Tychonis Brahe Dani Observationes septem Cometarum. Ex libris 
manuscriptis qui Havnise in magna bibliotheca Eegia adservan- 
tur nunc primum edidit F. E. Friis. Havnise, 1867. 4to, viii. + 
120 pp., 5 plates. 

Die Ruinen von Uranienborg und Stjerneborg im Jahre 1868. Von 
H. L, d' Arrest. Astronomische Nachrichten, Ixxii. pp. 209-224. 

Tycho Brahe und seine Verhaltnisse zu Meklenburg. Von G. 0. F. 
Lisch. Jahrbucher des. Vereins flir meklenburgische Gescliichte, 
xxxiv. 20 pp., 8vo. 

Minder om Tyge Brahes Ophold i Bohmen. Af F. R. Friis. Dansk 
Tidsskrift, i., 1869, 8vo, pp. 225-236 and 257-269. 

Tyge Brahe's Haandskrifter i Wien og Prag. Af F. R. Frii.?. 
Danske Samlinger, iv., 1869, 8vo, pp. 250-268. 

Danske Magazin. Fjerde Esekke. 2'"' Bind. Bidrag til Tyge 
Brahes Historie, af H. J. Rordam, pp. 16-34; Bidrag . . . af 
F. R. Friis, pp. 324-328. [About Gellius ; list of some of 
Tycho's pupils ; the sale of Knudstrup ; Parsbjerg's complaint 
of Jessenius, above, p. 311, footnote.] 

396 NOTES. 

Tyge Brahe. En historisk Fremstilling efter' trykte og utrykto 
Kilder af F. E. Friis. Kjobenhavn, 1871. 8vo, 386 pp. 

" Tyge Brahe, en historisk . . . af F. R. Friis," kritisk betragtet af 
J. Dreyer. Kjbbenhavn, 1871. 8vo, 19 pp. 

Joannis Kepleri Astronomi Opera Omnia. Ed. C. Frisch, 8 vols. 
FrankofurtietErlangse, 1858-71. 8vo. [Contains many abstracts 
from letters between Tycho and Kepler, and the Vita Kepleri in 
vol. viii. is a valuable source for the last years of Tycho's life.] 

Tycho Brahe und J. Kepler in Prag. Fine Studie von Dr. J. von 
Hasner. Prag, 1872. 8vo, 47 pp. 

Breve og Aktstykker angaaende Tyge Brahe og hans Slsegtninge. 
Samlede og udgivne af F. E. Friis. Kjbbenhavn, 1875, 8vo 
169 pp. 

Tyge Brahes meteorologiscke Dagbog holdt paa Uraniborg for 
Aarene 1582-1597. Udgiven af det kgl. danske Videnskabernes 
Selskab. Kjbbenhavn, 1876. 8vo, iv. + 263 + Ixxv. pp. 

On a portrait of Tycho Brahe. By Samuel Crompton. London, 1878 
(Mem. Lit. Phil. Soc. of Manchester, vol. vi. pp, 77-81 [compare 
Nature, xv. p. 406 and xvi. p. 501]. 

Tychonis Brahei et ad eum doctorum virorum Epistolae ab anno 
1568 ad annum 1587 nunc primum collectae et editae a F. E. 
Friis. Havniae, 1876-86. 4to, 112 pp., 2 plates. 

Astronomische, meteor, und magn. Beobachtungen an der K.K. 
Sternwarte zu Prag im Jahre 1 880. 4to [on pp. iii.-iv. about 
some instruments at Prague alleged to have been Tycho's]. 

F. Dvorsky : Novd zpravy o Tychonu Brahovi a jeho rodine. Pub- 
lished in the Casopis Musea Kralovstvi Ceskeho, vol. Ivii., 1883, 
pp. 60-77. 

Carteggio inedito di Ticone Brahe, Giovanni Keplero e di altri celebri 
astronomi e matematioi dei secoli xvi. e xvii. con Giovanni 
Antonio Magini. Tratto dalP Archivio Malvezzi de' Medici in 
Bologna, pubblicato ed illustrato da Antonio Favaro. Bologna, 
1886. 8vo, 522 pp. 

Tychonis Brahe Triangulorum planorum et sphaericorum Praxis 
Arithmetioa. Qua maximus eorum, praesertim in Astronomicis 
usus compendiose explicatur. Nunc primum edidit F. I. Stud- 
ni6ka. Pragae, 1886, 4to, 2 + 20 If. [Facsimile.] 

Aus Tycho Brahe's Briefwechsel. Von F. Burckhardt. "Wissen- 
schaftliche Beilage zum Bericht liber das Gymnasium 1886-87. 
Basel, 1887. 4to, 28 pp. 

Elias Olsen Morsing og hans Observationer. Ved F. R. Friis. 
Kjbbenhavn, 1889. 8vo, 28 pp. and 4 plates. 


Aalboeg, friend of T., 23. 

Abul Hassan, inclination of lunar 

orbit, 343, 
Abul Wefa, armillEe, 316; meridian 

circle, 318 ; lunar variation, 339. 
Accuracy of T.'s observations, 356, 


Ahmed Ibn Abdallah, eclipse of 
year 829, 323. 

Al Batraki, trepidation, 355. 

Al Battani, time determinations, 
323 ; iixed stars, 354 ; trepida- 
tion, 355. 

Albumassar, distance of comets, 48. 

Al Chogandi, sextant of, 326, 328. 

Alhazen, refraction, 80, 334, 336. 

Almegist, translations of, 3, 347. 

Alpbonsine tables, 3, 18, 19, 30, 52, 

54. 133, 145, 155. 175. 334. 355- 
Al Sagaui, quadrant of, 328. 
Altitudes for time determinations, 

323, 325- 
Alzerkali, trepidation, 355. 
Andreas, servant of T., 272 ; pupil 

of T, 275. 
Annual equation, 306, 339, 340. 
Apianus, Peter, book on astronomy, 

6, 79 ; direction of comets' tails, 

45, 1 65; latitude of Konigsberg, 

Apianus, Philip, son of Peter, 34. 
ApoUonius of Perga, planetary 

system of, 274, 304. 
Arbuthnot suggests to publish T.'s 

observations, 375. 
Argelander, place of Nova, 67 ; 

accuracy of T.'s observations, 356. 
Aristarchus, solar system, 167. 
Aristillus used armillse, 315. 

Aristotle, ideas about comets, 63, 

ArmillaB, 315. 
D'Arrest, region about Nova, 67 ; 

ruins at Hveen, 379. 
Assistants, 117, 280, 28S, 302, 381, 

Astrolabium, 316, 318. 
Astrology, practice of, 21, 24, 49, 

54, 68 ; oration on, 74 ; calendar, 

133; principles of, 146; T.'s 

opinion of, 155, 384. 
Augsburg, T.'s visits to, 30, 81. See 

Augustin on T.'s meridian line, 359. 
Aurora observed at Hveen, 206. 
Axelsen, Cort, assistant to T., 215, 

Azimuth, circles, 321; supposed 

error of, 358. 

JjACHAZEK, rector, Prague Univer- 
sity, 303. 
Bachmeister, professor at Eostock, 

26, 308. 
Barleben succeeds T. at Hveen, 376. 
Barneweld, Dutch statesman, 270. 
Bartholin, E., prepares to publish 

T.'s observations, 373, 374. 
Barwitz, Austrian statesman, 269, 

278, 369. 
Basle, visits to, 29, 81 ; T. proposes 

to live at, 84. 
Battus, professor at Eostock, 25. 
Behaim, geographer, 5. 
Below, friend of T., 155, 163, 384. 
Benatky Castle, description, 281 ; 

new buildings, 286 ; T. leaves, 





Bessarion, Cardinal, 3. 
Beza on new star, 68. 
Bibliography of books and memoirs 

of T., 392. 
Bille, Beate, mother of T., II, 138, 


Eske, relation of T., 284, 308, 

• Steen, uncle of T., 26, 9I, 127, 

Blaev, pupil of T., 26, 91, 127 ; his 

son a printer, 374. 
Bohemia, state of, 278. 
Bongars, French historian, 137. 
Books by T., 44, 162, 181, 182, 368, 

369. 370- 
Bording, chancellor of Mecklenburg, 

Brahe, family, 10. 

Axel, brother of T., 283. 

■ Cecily, daughter of T., 72, 367. 

Christine, daughter of T., 72. 

Claudius, son of T., 72. 

Elizabeth, daughter of T., 72, 

300, 301, 367. 

Erik (Count Visingsborg), 310. 

Jorgen, uncle of T., 12, 22. 

Jorgen, son of T., 72, 294, 366. 

Jorgen, nephew of T., 376. 

Magdalene, daughter of T., 72, 

73, 224, 283, 366, 367. 

Otto, father of T., 11, 35. 

Sophia, sister of T., 12, 71, 73, 

201, 302, 306, 367. 

Sophia, daughter of T., 72, 


Steen, brother of T., 35, 223, 


Tyge (Tycho), son of T., 72, 

265, 283, 293, 366. 

Brandeis Castle, 281. 
Brandenburg, Elector of, intercedes 

for T., 25s, 258. 
Braun's map of Hveen, 90, 91, 94, 

Brucaeus, professor at Eostock, 131, 

133. 163, 242. 
Brunswick, Henry Julius, Duke of, 

visits T., 205 ; Otto of, wants 

horoscope, 285. 
Buchanan, portrait of, 100, 203. 

Biirgi, improves instruments, 120, 
i34> 212, 331; clocks, 324; 
trigonometrical formulse, 361. 

Busch on new star, 64. 

Calendar for 1573, 42, 52; for 

1586, 125 ; for King, 156. 
Camerarius, Joachim, at Leipzig, 


— — - Elias, at Frankfurt-on-the- 
Oder, on new star, 60, 61, 63. 

Canonry. See RoskUde. 

Capuchins at Prague, 280. 

Cardanus, 69, 166, 349. 

Carellus, ephemerides, 18. 

Carl Gustav, King of Sweden, 377. 

Cassel observatory, 57, 79, 120, 134, 

Cassiopea, stars of, 39, 47, 328, 353. 
See New star. 

Chanzler, inventor of transversals, 


Chemical studies of T., 36, 128. 

Chiaramoute on distance of comets, 
160, 371. 

Chinese observations, 315, 343. 

Christian IV. elected to the crown, 
140 ; succeeds to it, 198 ; visits 
Hveen, 214 ; coronation, 230 ; T.'s 
letter to,' 243 ; reply, 248 ; mar- 
riage, 256 ; T. sends books to, 267. 

Christine, T.'s wife, 70, 366. 

Chytraeus, professor at Rostock, 24, 
62, 242. 

Clavius, subdivision of arcs, 223, 
329 ; trigonometrical formulas, 

Clepsydrse, 324. 

Clocks, 324. 

Colding, pupil of T., 302. 

Cologne, Elector of, T. applies to, 
269, 270. 

Comets, different classes of, 45 ; 
nature of, 63, 160; parallax, 48, 
131, 165, 208, 305; direction of 
tails, 6, 45, i66, 170; comet of 
1577. 131. 158 ; book on, 162, 272 ; 
six other comets, 160, 161, 162. 

Compass, T. repairs King's, 144. 

Computing, 360. 



Conjunctions of planets, i8, 52, 194, 

Copenhagen University, 13, 94, i lo ; 
T.'s house at, 200, 239. 

Copernicus, life, 6 ; oommentariolus, 
S3 ; instrument, 103, 125 ; obser- 
vations, 1 23 ; solar system, 6, 172, 
1 80, '208 ; T.'s opinion of this, 74 ; 
solar theory, 132, 333, 337 ; lunar 
theory, 338. 

Corraducius, German Vioe-Chancel- 
lor, 223, 266, 269, 271, 279, 298. 

Correspondence, 131 ; with Land- 
grave and Rothmann, 134, 135, 
208, 209, 228; with Magini, 212, 

Cosmopolitan character of astro- 
nomy, 115, 261. 

Courland, Prince of, visits T., 217. 

Craig, John, distance of comets, 20S, 

30s. 369. 

Crol, T.'s instrument -maker, 127, 

Cross-staff, 19, 357, 381. 

Curtius, Albert, edits T.'s observa- 
tions, 371, 372. 

Curtius, J., German Vice-Chancel- 
lor, 223, 262, 329 ; his house at 
Prague inhabited by T., 278, 299, 

Customs at Elsiuore, grant from, 

109, H2. 
Cyprianus. See Leovitius. 

Uancby, French envoy, 42, 73, 85, 

93. 131- 
Danti, obliquity of ecliptic, 355. 
Dee on new star, 63. 
Diameter of sun, moon, planets, 

191 ; of stars, 191 ; of moon, 344. 
Diary, meteorological, at Hveen, 

Digges on new . star, 58, 59 ; on 

transversal divisions, 330. 
Dimensions of universe, 191. 
Directions, astrological term, 148, 

Disciples. See Assistants. 
Dresden, T.'s visit to, in 1598, 271. 
Duel of T. and Parsbjerg, 26. 

Eclipse of sun, 1560, 13; 1567, 
27; 159S, 258, 259, 280, 341 ; lunar, 
21, 26, 53, 55, 272 ; observations 
of eclipses used for lunar theory, 
337 ; total eclipses denied by T., 

Ekdahl on ruins at Hveen, 378. 

Elegy to Urania, 55 ; to Denmark, 

Elias Olsen, assistant to T., life, 

122 ; expedition to Fraueuburg, 

123 ; calendar for 1586, 125. 

Elixir of T., 130, 283. 

Endowments of T., 108-113. 

Ephemerides of Carellus, 18 ; Ever- 
hard, 269 ; Eegiomontanns, 5 ; 
Stadius, 14, 17. 

Eriksen, assistant to T., 301, 367. 
Estate of T., 35, 223 ; promised in 
Bohemia, 279. 

Pabeicius, David, visits T., 260, 

Pabricius, Paul, on new star, 60, 61. 
Farms, eleven, granted to T., 109, 

235, 257- 
Ferdinand I.'s villa inhabited by 

T., 298, 303. 
Ferdinand II., Emperor, 2gr, 367, 

Fincke, mathematician, 'mission to 

Hveen, 240. 
Fishponds at Hveen, 114, 257. 
Flemliise, assistant to T., 117 ; me- 
teorology by, 119 ; sent to Cassel, 

Fool, T.'s, 128. 
Forts, ancient, at Hveen, 91. 
Fracastoro on direction of comets' 

tails, 6, 166 ; on obliquity of 

ecliptic, 355. 
Frandsen, Hans, friend of T., 14, 

44, "5- 

Frangipani on new star, 64. 

Frauenburg, expedition to, 123. 

Frederick II, interested in T., 28; 
desires him to lecture, 73 ; gives 
him Hveen, 84 ; other grants, 
108 ; whether he visited T., 139 ; 
kindness to T., I4t ; death, 156; 



had intended to perpetuate ob- 
servatory, 200. 

Trederiok III., 264, 373, 374- 

Frederick "V., Elector Palatine, 365. 

Friis, Chancellor, enemy of T., 230, 
231, 236, 242. 

Froben, printer, 253. 

Funeral of T., 310. 

Gtanz, chronologist, 303. 

Gellius Sascerides, pupil of T., 121 ; 

travels abroad, 181 ; intercourse 

■with Magini, 212, 213; quarrel 

with Tycho, 224. 
Gemma, Cornelius, on new star, 58, 

60, 62, 63, 68; comet of 1577, 

16S, 171- 
Gemma, Frisius, on cross-staff, 20 ; 
direction of comets' tails, 45, 166 ; 
instruments belonging to, 107 : 
astronomical rings, 316^ 
Gemperlin, painter, 82, loi. 
Geographical studies of T., 142, 358. 
Germany, revival of learning in, 2. 
Girsitz, in Bohemia, T.'s residence 

there, 283. 
Globe, great, 32, 82, 99, 366 ; small, 

46, 2l5. 
GoggingeV, near Augsburg, 30. 
Gosselin on new star, 63. 
Graminseus.on new star, 68. 
Grant of 6000 daler, 199. 
Greek astronomy, I. 
Gregorian calendar, 132, 280. 
Gustavus Adolphus, alleged pro- 
phesy on, 196. 
Gyldenlove, 376. 
Gyldenstjern, cousin of T., 118, 284. • 

HagbciuS on new star, 58, 64 ; 
meeting with T., 82 ; corresponds 
with T., 120, 131, 269, 270; par- 
allax of comets, 131, 165, 171 ; 
receives T. at Prague, 279 ; death, 

Hainzel, J. B., 30. 

Hainzel, Paul, 30 ; quadrant con- 
structed for him by T., 31 ; 
observes new star, 60, 62 ; corre- 

sponds with T., 81, 131 ; observa- 
tions of sun, 334. 
Hannov sends T. the instrument of 
Copernicus, 125. 

Hansen, assistant to T., observes 
comet of 1593, 162; eclipse of 
1598, 259. 

Hardeck, on former apparitions of 
new stars, 66. 

Hasenburg, alchemist. 303. 

Heiberg, on ruins at Hveen, 379. 

Helsingborg Castle, 35. 

Hemmingsen, theologian, 178, 203. 

Henry III. of France, 69. 

Heridsvad Abbey, 35, 73. 

Hervart von Hohenburg, correspon- 
dent of Kepler, 292, 297, 340, 

Hind observes region around Nova, 

67 ; orbits of comets, 162. 
Hipparchus, star alleged to have 
been seen by him, 47, 49 ; obser- 
vations of, 315 ; time-stars, 322 ; 
lunar inclination, 342 ; longitude 
of stars, 348, 354. 
Hoffmann, Baron, friend of T. and 

Kepler, 292, 293, 296, 299. 
Hoik, H., no. III ; Ditlev, 236. 
Homilius, Profe.ssor, at Leipzig, 16, 

17, 20, 330. 
Horoscopes prepared by T., 20; of 
Prince Christian, 144 ; of two 
other princes, 154 ; wanted by 
Duke of Brunswick, 285. 
Horrox, amount of annual equation, 

Huet, account of T.'s quarrel with 
Valkendorf, 233 ; visits Hveen, 

377. 389- 

Hulsius, bookseller, 370. 

Hveen, island, offered to T.. 85 ; 
first visit to, 86 ; gr.nnted for life, 
86 ; description of, 88 ; traditions 
about, 92; life at, 114; plan of 
granting it to T. for ever, 140 ; 
tenants at, 116, 236; clergyman 
at, 236 ; disturbances at, 240 ; T.'s 
opinion about, 256, 267, 375 ; kept 
by T. after departure, 284 ; subse- 
quent fate, 275, 389. 



Ibn Carfa, on giant instruments, 

Ibn Yunis used armillse, 316 ; time 
determination bv altitudes, 323 ; 
lunar inclination, 343 ; trigono- 
metrical formulas, 361. 

Inclination of lunar orbit, 342. 

Income of T., 257, 279. &e Endow- 

Instruments of T., descriptions of, 
19, 38, loi, 103, 107, 211 ; dis- 
mantled, 235 ; illustrated account 
of, 260 ; brought to Prague, 279, 
283, 284; principle of, 317; sub- 
sequent fate, 365, 366, 368. 

Interregnum, 198. 

Iser River, 282. 

James TI. visits T., 202. 

Jeppe, T.'s fool, 128. 

Jessenius of Wittenberg, 272, 295, 

296, 311. 
Joestelius, assistant to T., 28S, 302, 

Johannes of Hamburg, assistant to 

T., 280. 

JvAAS, Chancellor, 115, 198, 199, 
211, 222. 

Karen, Andersdatter, 376. 

Kepler, J., dates revival of astronomy 
from Tyoho, 20 ; iirst correspon- 
dence with T., 259, 266 ; early 
life, 289 ; joins T., 293 ; quarrels 
with him, 295, 296 ; reconciled, 
297 ; returns to Gratz, 297 ; settles 
at Prague, 299 ; new quarrel, 300 ; 
theory of Mars, 303, 304, 305 ; re- 
futation of Eeymers, 304; at T.'s 
death, 309, 386 ; later work, 312 ; 
annual equation, 341 ; on solar 
excentricity, 346 ; T.'s successor 
at Prague, 365 ; publishes T.'s 
bools;, 368 ; report on his unpub- 
lished works, 370; uses and re- 
tains T.'s MSS., 370 ; intends to 
publish them, 371. 

Kepler, L., son of J. Kepler, pos- 
sessed T.'s MSS., 374 ; sells them, 

Knieper, painter, loi. 

Knudstrup, T.'s estate, 11, 35, 223, 

Krag, professor at Copenhagen, 225. 
Kronborg Castle, 85, loi, 140, 143. 
KuUagaard, loS. 
KuUen lighthouse, 108, 109. 

Lacaille, orbit of comet, 1593, 

La Hire, 375. 

Lange, friend of T., 183, 201, 274, 

Latitudes, geographical, supposed to 
vary, 213, 263. 

Lectures by T., 73. 

Leipzig University, 16. 

Leopold, Bishop of Passau, 367. 

Leovitius, Cyprianus, 29, 63, 65. 

Liddel, mathematician, 137, 184. 

Lindauer, early observation of new 
star, 62. ' 

Live, maid in T.'s house, 127. 

Longitudes, absolute, 348 ; T.'s plan, 
349 ; determined at Cassel, 352. 

Longomontanus, assistant to T., 
his youth, 126; leaves T., 241; 
observes eclipse of 1598, 259 ; T.'s 
letter to him, 268, 283, 287 ; 
travels, 272 ; arrives at Prague, 
288 ; works on lunar theory, 294, 
305. 339 ; on Mars, 294, 303 ; re- 
turns to Denmark, 299 ; inscrip- 
tion on globe, 366. 

Louis XIV., 374. 

Liibeck, Bishop of, 266. 

Lunar theory, 187, 294, 305, 338. 

Luther, his horoscope, 69 ; his 
opinion of Copernican system, 177. 

Maestlin, new star, 59 ; comet of 
1577. 17I) '81 ; Kepler's teacher, 
289 ; consulted by Kepler, 297. 

Magdeburg, T.'s instruments at, 
278, 285. 

Magini, T. sends him book on comet, 
181 ; corresponds with T., 212, 
262, 271 ; observes Mars, 214 ; 
book on instruments sent to him, 
266 ; criticises T.'s lunar theory, 
339 ; prostaphseresis, 362. 



Magnitudes of stars, 354. 

Maitland, Scotch chancellor, 203, 

Major, Johannes, 131, 132. 

Manuscripts, T.'s, 370, 373, 374, 390. 

Marcellinus, star mentioned by, 65. 

Marius, Simon, 302. 

Mars, distance of, 178 ; theory of, 
213, 303, 346; oppositions ob- 
served, 214, 258, 303. 

Mashallah, on astrolabes, 316. 

Mathematical studies, 23, 40. 

Maurice of Hesse, 212, 285. 

Maurolycus on new star, 62. 

"Mechanica," 260. 

Mecklenburg, Duke of, 133, 158, 

246, 270 ; T.'s money invested in, 

247, 308. 

Medal struck in 1595, 228. 

Medicine, connection with astro- 
nomy, 24, 118; T.'s practice of, 
129, 232, 260. 

Melanchthon, on Copernican system, 

Meragha observatory, 320, 321. 
Meridian observations, 321, 349 ; 

meridian line, 358, 388. 
Meteorological rules, 119 ; diary at 

Hveen, 122. 
Minkawitz, Imperial councillor, 309, 

Moestlin. See Maestlin. 
Monavius, Jesuit, 120, 182, 268. 
Money invested by T., 247, 308. 
Moon, observations of, 337 ; tables 

of, 337. See Lunar theory. 
Moryson, Fynes, traveller, 71, 89, 

Muhlstein, 286. 
MuUer, Johannes, assistant to T., 

259, 268, 287, 288, 300. 
Muffet, physician, 137. 
Mule, assistant to T., 240, 283. 
Munk, Admiral, 198, 215. 
Munosius, on new star, 60, 61, 83. 
Mysterium Cosmographicum, 289. 

N ASIE al-din Tusi, 320. 
Naturalisation of T. in Bohemia, 

Neisse, great globe brought to, 366. 

New stars alleged to have appeared 
in 945 and 1264, 65. 

star, 1572 ; Tycho's first obser- 
vations, 38 ; measures, 39 ; decline 
of light, 41 ; colour, 42 ; book by 
T. on, 44 ; nature of, 48, 63, 193 ; 
effect of, 49 ; other observations, 
57 ; parallax, 60 ; when first seen, 
61, 68, 193 ; whether it will appear 
again, 66 ; larger work on, 188. 

star, rumour of one in 1578, 

Newton quotes Gemma's statement 

about new star, 62. 
Nobility, Danish, 10. 
Nodes, lunar, motion of, 343. 
Nolthius on new star, 60. 
Nonius, 320, 329. 
Nordfjord estate, no, in, 231, 

Nose, T.'s, disfigured, 26, 71, 274. 
Novara, teacher of Copernicus, 7 ; 

geographicallatitudes, 213. 
Niimberg observatory, 4. 
Nunez. See Nonius. 

Obliquity of ecliptic, 123, 355. 

Observations by T., earliest, 19, 27, 
32, 35 ; of new star, 39, 41 ; in 
IS74. 73 ; at Hveen, 86, 94, 227 ; 
at Wandsbeck, 258 ; in Bohemia, 

Observatories, T.'s, 103, 200, 282, 

286, 333. 
Ohr, printer, 260. 
Orange, Maurice of, 266, 269. 
Oration on astrology, 74 ; funeral, 

Oxe, Peter, High Treasurer, 43 ; 
Inger, T.'s foster-mother, 43, 138, 

X APIUS, friend of Kepler, 292. 
Parallax of new star, 60 ; of comets, 

131, 165 ; of planets, 189, 303 ; of 

sun, 335 ; of moon, 344. 
Paris University, 15. 
Parsbjerg, his duel with T., 26. 
Pedersen, steward at Hveen, 259. 



Pension of 500 daler, 85, 108, 234. 

Peters on comet of 1585, 161 ; accu- 
racy of T.'s observations, 357. 

Peucer, professor at Wittenberg, 21, 
23, 57, 58, 182, 370. 

Picard, expedition to Hveen, 358, 

374, 377- 
Pinnules, improved, 331.' 
Planets, observations of, 227, 259, 

345 ; theory by T., 180, 345. 
Pliny, new star mentioned by, 42, 

Poetical effusions, 46, 55, 56, 115, 

Pontanus, assistant to T., 384. 
Portraits belonging to T., 100, 106 ; 

of Danish kings, 143 ; of Tycho, 

loi, 228, 263. 
Praetorius on new star, 61, 84. 
Prague, description, 28 1 ; T. settles 

finally at, 298. 
Pratensis, friend of T., 14, 42, 44, 46, 

73- 85, 87- 
Precession, 354. 

Printing-press, 115, 163, 260, 272. 
Progymnasmata, 186, 269, 272, 288, 

307, 368. 
Prostaphaeresis, 361. 
Prutenio tables, 8, 18, 19, 30, 52, 53, 

133. I4S. iSS. 175- 

Ptolemean system, 7, 172. 

Ptolemy, works of, 14, 347 ; quadrant 
of, 320; lunar theory, 338; star 
catalogue of, 347. 

Puehler's geometry, 331. 

Pupils. See Assistants. 

Purbach, 2 ; time determinations, 
323 ; whether he used trans- 
versals, 330 ; trepidation, 355 ; 
trigonometry, 360. 

yuADEANT, great, at Augsburg, 31, 
82 ; Tycho's, loi, 159, 320, 322. 

Kadius. See Cross-staff. 
Kaimundus of Verona on new star, 

61, 64, 83. • 
Eamus, mathematician, 33. 
Rantzov, friend of T.,. 116, 135, 253, 

269, 270, 284. 

Easmus Pedersen, tenant of T., 217. 

Eatisbon, coronation in 1575, 83. 

Eeduction of lunar motion to eclip- 
tic, 344. 

Eefraction first noticed, 80, 336 ; 
neglected by Copernicus, 123 ; 
T.'s researches on, 334 ; cause of, 
336 ; tables of, 265. 

Eegiomontanus, life, 3 ; epheme- 
rides, 5 ; trigonometry, 47, 360 ; 
instruments, 317, 330 ; trepida- 
tion, 355. 

Reinhold, 8, 18, 23, 124 ; his son, 83. 

Eeisacher on new star, 60, 64. 

Eeymers, Biir, on T.'s nose, 27 ; early 
life, 183 ; system of the world, 
184; slanders T, 268, 273; flies 
from Prague, 288 ; corresponds 
with Kepler, 290 ; T. takes pro- 
ceedings against him, he dies, 
304 ; rumour of his having 
poisoned T., 312 ; prostaphseresis, 

Ehodius, assistant to T., 302. 

Eoemer brings T.'e MSS. to Paris, 

Eoeslin on comet of 1577, 171 ; sys- 
tem of the world, 274^ 

Eogers, English envoy, 137, 182. 

EoUeuhagen, astrologer, 288, 312. 

Eosenberg, friend of T., 303, 309. 

Eosenkrands, Danish statesman, 
198, 199, 215, 230; his son, Hol- 
ger, 24s, 301, 302. 

Eoskilde, prebend, 28, 109, 217, 221, 
242 ; one granted to Flemlose, 
118 ; treaty of Eoskilde, 377. 

Eostock University, 24, 27 ; T.'s 
residence in 1597, 241. 

Eothmann, 121, 134, 181, 183, 184 ; 
visits T., 206 ; abused by Eeymers, 
273 ; still alive in 1599, 288 ; ab- 
solute longitude, 352. 

Eudolph II., 222, 261, 265, 277, 283, 
285, 298, 306, 307. 

Eudolphine tables, 301, 313, 365. 

Eumph, Bohemian statesman, 279. 

Saceobosco, 3. 

Safarik on region around Nova, 67. 
Salary. See Income. 



Salzburg, Archbishop of, 266. 

Saturn, orbit of, 180. 

Savelle, Thomas, T. sends letter to, 

Scallger, Joseph, T. corresponds 
with, 255, 266, 270. 

Schjellerup, orbit of comet 1580,161. 

Schbnfeld, Victor, professor at Mar- 
burg, 127. 

Schreokenfuchs, 82. 

Sohuler, Wolfgang, professor at Wit- 
tenberg, on new star, 58, 83. 

Scripture and Copernioan system, 

Scultetus, studies at Leipzig, 16 ; 
teaches T. about transversals, 20, 
330; corresponds with T., 131, 
133; on comet, 1577, 171 ; T. sends 
him a book, 182 ; T. consults him 
about printing, 288, 369. 

Seccerwitz, poet, visits T., 136. 

SeifEart, assistant to T., 302. 

Sextant, 32, 38, 159, 325, 326. 

Sights, improved, 331. 

Sjoborg, Swedish antiquarian, 91, 

SneDius, 371. 
Sorensen, king's physician, enemy 

of T., 232. 
Soliman, Sultan, death foretold by 

T., 26. 
Sophia, Queen, 138, 198, 200. 
Stadius, ephemerides, 14, 17. 
Stags, 210. 

Star in Cassiopea. See New star. 
Stars, fixed, observations of, 164, 

351. 353; catalogue of, 227, 265, 

347> 352, 353. 
Stenwinchel, architect, 93, loi. 
Stjerneborg, description, 103 ; ruins 

of, 378. 
Stub, Professor, sent to Hveen, 240. 
Sun, observations of, 94, 333 ; orbit 

of. 333. 346. 
System of the world. &e Copernicus, 
Ptolemy, Eeymers, Tycho. 

lABlT ben Korra on trepidation, 

354. 355- 
Tampaoh, publisher of T.'s books, 

369. 370 

Tenants at Hveen, 116, 235, 267; on 
the estate of the Eoskilde prebend, 

Tengnagel, assistant to T, 242, 367 ; 
sent to Holland, 269 ; brings 
letter to Kepler, 293 ; Kepler's 
wife complains of him, 300 ; mar- 
ries T.'s daughter, 301, 302 ; in- 
tends to prepare planetary tables, 
365; gives it up, 312 ; subsequent 
career, 367 ; edits T.'s book on 
comet, 369 ; agreement with 
Kepler about MSS., 370. 

Teynkirohe at Prague, T. buried 
there, 310. 

Thau, Valentin, mathematician, 16. 

Theatrum astronomicum, proposed 
work by T., 182, 370. 

Theon, first mention of trepidation, 

Thott, Otto, brother-in-law of T., 

201 ; Tage, nephew, 201. 
Time determinations, 159, 258, 322. 
Timocharis used armillse, 315. 
Tomb of T., 311. 
Torquetum, instrument not used by 

T., 317. 
Traditions about Hveen, 92. 
Transversal divisions, 20, 330. 
Trautson, Emperor's chamberlain, 

Trepidation, 262, 354, 355. 
Trigoni, astrological term, 49, 195. 
Trigonometry, development of, 4, 

360, 361. 
Triquetrum, 58, 83, 84; not much 

used by T., 322. 
Twilight, duration of, 206. 
Tychonic system, 167, 180, 303. 

Ulfstand, Governor to Prince 

Christian, 215. 
Ulrioh, Prince, recovers great globe, 

Uraniborg, description, 93 ; life at, 

114; ruins of, 377, 378. 
Ursus. See Eeymers. 

V ALESIUS on new star, 60, 64. 
Valkendorf, chief of Exchequer, 87 



112; one of four protectors of the 
kingdom, 198 ; alleged quarrel 
with T., 216 ; High Treasurer, 
230; believed to have been T.'s 
enemy, 232, 233 ; T. asks his help, 
267, 283. 

Variation of the lunar motion dis- 
covered by T., 262, 338, 339. 

Vedel, tutor to T., 15, 17, 20, 23 ; 
collects ancient ballads, 91, 92; 
corresponds with T., 131, 279, 283 ; 
visits T., 138, 201 ; dismissed from 
office of historiographer, 252. 

Venice, T. visits, 81 ; intended ex- 
pedition to Egypt from, 263. 

Venus, comet's tail pointing to, 167, 
170; used for determining abso- 
lute longitude, 349. 

Vernier, 329. 

Vifete, 361. 

Vignettes in T.'s books, 128. 

Vitello, mentions refraction, 336. 

Wallbnstbin, patron of Kepler, 

Walter, Michael, declaration about 
Reymers, 275. 

Walther, Bernhard, 4 ; on refrac- 
tion, 80, 336 ; instruments, 316, 
330 ; time determination, 323 ; 

observations of sun, 333 ; of 
planets, 345 ; of stars, 348. 

Wandsbeck, 253. 

Werner on trepidation, 355. 

Wilhelm IV., Landgrave of Hesse, 
on new star, 57, 65, 68, 321 ; his 
youth, 79 ; T. visits him, 80 ; 
recommends T. to king, 84 ; alters 
his instruments, 120 ; correspon- 
dence with T., 134, 209, 228 ; 
intends to visit T., 136 ; on comet 
of 1577, 171 ; reads book on 
comet, 181 ; death, 212. 

Willoughby d'Eresby, Lord, 137. 

Winstrup, Bishop, 236, 377. 

Wittenberg University, 22, 72, 271 ; 
T. visits, 29, 83, 271, 340. 

Wittich, stay at Hveen, 119 ; never 
returns, 120 ; tells T. about Hage- 
cius, 132 ; at Cassel, 120, 134, 331, 
332 ; his books sold, 268 ; pro- 
staphseresis, 361. 

Woldstedt, orbit of comet, 1577, 357. 

Wolf, Hieronimus, at Augsburg, 33, 

Workshop at Hveen, 108. 

Wiirtemberg, Duke of, 370. 

Young, Peter, 100, 203. 










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